The Legend of the Blue Sea

The short briefing before you dive in.

CompletedFATED ROMANCE PICK

The Legend of the Blue Sea

푸른 바다의 전설 (Pureun badaui jeonseol) · 2016 · South Korea

WriterPark Ji-eun

DirectorJin Hyuk, Park Seon-ho

Episodes20 eps · ~65 min each

Where to Watch✅ Viki, Netflix, Hulu

⏱️

Binge Time21h 40m

AiredNov 16, 2016 – Jan 25, 2017

GenreFantasy · Romance · Comedy

Content Rating15+

SBSVikiNetflixHulu

ReincarnationMermaid RomanceCon ArtistFated LoveInterspecies Romance

Everything you need to decide, in one place.

The reincarnated pairing — and the con-artist family, stepfamily, and mermaid mythology surrounding them.

Gianna Jun

Sim Chung / Se-hwa

Lead

Lee Min-ho

Heo Joon-Jae / Kim Dam-Ryung

Lead

Lee Hee-jun

Jo Nam-Doo

Supporting

Shin Won-ho

Tae-O

Supporting

Shin Rin-a

Seo Yoo-na

Supporting

Shin Hye-sun

Cha Shi-ah

Supporting

Moon So-ri

Ahn Jin-joo

Supporting

Na Young-hee

Mo Yoo-ran

Supporting

Hwang Shin-hye

Kang Seo-hee

Supporting

Oh Yeon-ah

Young Kang Seo-hee

Supporting

Lee Ji-hoon

Heo Chi-hyun

Supporting

Park Hae-soo

Hong Dong-pyo

Supporting

A spoiler-light refresher, episode by episode.

EP 01

The Woman Who Won’t Leave

Nov 16, 2016

A 1598 storm washes a mermaid ashore into a corrupt nobleman’s hands, and centuries later a Spanish hotel room becomes the exact same trap for con artist Heo Joon-Jae — except this time the mermaid, disguised as a strange, insistent woman, refuses to leave. Joon-Jae notices her jade bracelet first, not her. It’s identical to the one his Joseon-era counterpart wore, and neither man asked for it back.

EP 02

Into the Ocean

Nov 17, 2016

Dam-Ryung learns mermaids can hear thoughts; Joon-Jae learns Sim Chung can’t take a hint. He dumps her at a department store, feels a rare flicker of conscience, and comes back — only to be dragged into a rooftop chase by a CEO he swindled. Cornered on a cliff with a fear of both heights and water, he gets pulled into the ocean by the one person willing to save him, and watches her turn into exactly what he doesn’t believe in.

EP 03

The Kiss That Erases

Nov 23, 2016

Sim Chung kisses Joon-Jae underwater and erases his memory of her — the same trick, it turns out, a mermaid named Se-hwa used on a drowning boy centuries earlier. He wakes up on a beach with a bracelet and no explanation. She starts walking to Seoul anyway, because he mentioned it once, in passing, the way people say things they don’t expect to be held to.

EP 04

A Memory Without Her

Nov 24, 2016

Joon-Jae’s flashbacks come back distorted — the chase, the fall, everything except the woman who caused them. Sim Chung, meanwhile, is getting arrested by aquarium security for acting like she belongs in the tank. He rescues her on instinct, using a fake badge, before he’s consciously remembered a single reason to. His housemates take one look at her and know something’s already decided itself.

EP 05

Moving In

Nov 30, 2016

Sim Chung moves into Joon-Jae’s house and starts absorbing her personality from television dramas, which is funnier in theory than in practice once Joon-Jae’s childhood friend Cha Shi-ah shows up sizing her up as competition. The comedy stops when a fugitive posing as a police officer tries to talk his way inside. Joon-Jae’s instincts catch what his memory can’t explain — that this stranger is a threat specifically to her.

EP 06

The Hand That Brought Her Back

Dec 1, 2016

A traffic accident nearly kills Sim Chung, and Joon-Jae’s search through every hospital in the city ends with her flatlining in front of him. She comes back the moment he takes her hand — not medicine, just repetition of something that already worked once, in a life he doesn’t remember. The driver turns out to be his own stepbrother, which tells him more about his family than the accident does.

EP 07

A Confession Disguised as a Test

Dec 7, 2016

Joon-Jae tells Sim Chung he loves her as a test, to see if she’ll say it back sincerely — and gets an answer more honest than he planned for. In the Joseon timeline, Dam-Ryung tracks down evidence that finally exposes Lord Yang’s murder of a merchant, buying Se-hwa’s freedom with proof instead of luck. Both timelines are learning the same lesson at different speeds: sincerity works better than the con.

EP 08

The Vase in the Museum

Dec 8, 2016

An ancient vase at Cha Shi-ah’s museum stops Joon-Jae mid-sentence — a man and a mermaid, painted centuries before he was born, and he can’t explain why it feels like a memory instead of an image. Sim Chung, running low on time she hasn’t told him about, gets a warning from a fellow merman: a mermaid’s heart hardens the longer she stays on land. Neither of them says out loud what they’re both circling.

EP 09

Don’t Leave Me

Dec 14, 2016

Joon-Jae finally confronts Ma Dae-Young and loses badly, bleeding out just long enough to say the thing he’s been avoiding — that he needs her to stay. It’s not strategic, it’s not a con, and that’s exactly why it works on her. Centuries earlier, Dam-Ryung is already preparing for an ending he can see coming, commissioning a portrait meant less as art than as a message to whoever comes next.

EP 10

The Portrait

Dec 15, 2016

A museum portrait does what months of flashbacks couldn’t — it hands Joon-Jae a face, a name, and the specific detail that mermaids erase memory with a kiss. He still doesn’t consciously connect the dots to Sim Chung, but his body starts reacting like it already knows. Nam-Doo, meanwhile, notices she heals too fast and asks too few questions about it, and starts drawing his own conclusions.

EP 11

Falling for a Con

Dec 21, 2016

Sim Chung finds out the men she’s living with are professional con artists and leaves — not because it changes how she feels, but because it changes how she sees herself for falling for it. Joon-Jae, hearing her thoughts clearly for the first time, finally understands what she is and what he’s about to lose. The episode ends on two threats closing in from opposite directions: a detective with a warrant, and a killer with a memory of his own.

EP 12

The Taxi Driver

Dec 22, 2016

Joon-Jae lets himself get arrested quietly rather than risk alarming her, while Ma Dae-Young — disguised as a cab driver — takes Sim Chung somewhere no one will look. Her warning that touching her erases memory backfires beautifully, flooding him with the exact past he’s spent this whole series trying to recover. Joon-Jae talks his way out of custody and arrives in time, which is less about heroics than about finally listening to her.

EP 13

The Name He Called Out

Dec 28, 2016

Joon-Jae wakes up calling out a name that isn’t hers, and Sim Chung spends the rest of the episode quietly working out what that means about a woman he doesn’t remember loving. It’s a small insecurity dressed up as a big one — she’s not competing with a person, she’s competing with a version of himself he hasn’t caught up to yet. He keeps a promise instead of running one more scam, which is its own kind of answer.

EP 14

What Hypnosis Remembers

Jan 4, 2017

Hypnosis gives Joon-Jae what nothing else could: the full memory of dying as Dam-Ryung to protect Se-hwa, and of her decision not to survive him. It’s not a twist so much as a debt coming due — he now knows exactly what he’s trying to prevent from happening twice. Ma Dae-Young gets his own partial memory back and realizes someone else threw the spear that killed him, which means the story has a suspect it hasn’t named yet.

EP 15

The Truth, Finally

Jan 5, 2017

Sim Chung’s health starts failing in a way no hospital can explain, and Joon-Jae finally says out loud what he’s known for a while — that he remembers everything, and that he knows exactly what she is. Her fear had always been rejection, not exposure, so the confession lands as relief instead of catastrophe. He also lies to her about how their past lives ended, which is either mercy or a mistake he hasn’t paid for yet.

EP 16

The Reunion She Planned

Jan 11, 2017

A birthday party becomes a reunion Sim Chung engineered without telling anyone — Joon-Jae’s estranged mother, brought back after years apart. It’s the warmest hour the show gives its side characters, and it earns the sentiment instead of rushing it. Elsewhere, a bump on the head gives Nam-Doo a memory of Sim Chung he was never supposed to keep, proof the erasing trick has an expiration date nobody planned for.

EP 17

The Spear

Jan 12, 2017

Erasing Ma Dae-Young’s memory costs Sim Chung more than she expects — it drags her through Se-hwa’s final moments, watching Dam-Ryung take a spear meant for her. The comforting lie Joon-Jae told earlier about their past ending happily collapses in real time. Their present catches up just as fast: Joon-Jae’s father is poisoned by his own wife, and dies before Joon-Jae can get him out of that house.

EP 18

The Confession Trap

Jan 18, 2017

Grief turns into a plan: Joon-Jae runs the sting of his life, provoking his stepmother into confessing to years of poisoning — including, finally, his father — with a detective recording every word. Sim Chung’s borrowed glimpse into Seo-Hee’s past confirms what nobody could prove until now. She’s arrested at the funeral, which is either the coldest place to do it or the only place it would actually land.

EP 19

The Shot

Jan 19, 2017

Chi-Hyun grabs a gun in the collapse of his mother’s arrest, and Sim Chung — remembering exactly how this scene ends for people she loves — steps in front of it before she can think better of it. She survives, barely, and falls into a coma that turns Joon-Jae’s victory over the show’s villains into the worst night of his life. Ma Dae-Young is finally caught, and Chi-Hyun doesn’t survive his own guilt, but none of it feels like winning.

EP 20

A Record That Outlasts Erasing

Jan 25, 2017

Sim Chung chooses the ocean over dying on land, erasing Joon-Jae’s memory once more before she goes — except this time she leaves a pearl, and he leaves himself a record. Three years later, now a prosecutor, he’s carrying a grief he can’t name until she returns. He hands her proof he never really forgot: notes on every moment neither of them was supposed to remember, finally strong enough to outlast the thing that kept erasing it.

Spoilers from here on — what actually happened, and why it lands.

What Actually Happened Sim Chung returns to the sea to survive, erasing Joon-Jae’s memories one final time and leaving him only a pearl. Three years later, now a prosecutor, Joon-Jae is pulled back to her the moment she returns to land — and reveals he anticipated losing his memory, so he wrote everything down. They reunite for good, and the show explicitly closes the loop it opened four hundred years earlier: this is the first version of Dam-Ryung and Se-hwa’s story where nobody dies for the other one.

Breaking the Four-Hundred-Year Loop The entire Joseon storyline exists to set up one rule: whenever a mermaid loves a human on land, someone pays for it with their life. Dam-Ryung dies protecting Se-hwa; she doesn’t survive losing him. The present-day couple gets a version of that same threat — Sim Chung’s failing health, Joon-Jae’s stepmother’s violence — and the show’s actual twist is a choice, not a plot mechanism: Joon-Jae refuses to let memory erasure mean the story resets to zero every time.

The Pearl and the Record — Why Physical Proof Matters Every earlier memory-wipe in this show was total — the human forgets, and the years the mermaid spent building a life evaporate with them. The pearl Sim Chung leaves behind isn’t a trinket, it’s the first time she consciously chooses to leave evidence a version of him might find again. Joon-Jae’s own notebook mirrors that instinct on his side: two people independently deciding that love shouldn’t be this erasable, without either one being told it was a solution.

What Happens to Everyone Else Nam-Doo and Tae-Oh end up living with Joon-Jae’s mother, an unconventional found family built entirely out of people who lost their original ones — Yoo-Ran to abandonment, the two con artists to circumstances the show never fully explains and doesn’t need to. Kang Seo-Hee and Chi-Hyun’s arc closes far less gently: her confession and his death mean the show’s one truly evil bloodline doesn’t get a redemption pass, only consequences.

The KDW Verdict The Legend of the Blue Sea spends twenty episodes asking whether a story built on tragedy can end any other way, and it answers with the least cynical option available: yes, if the people in it actually try. It’s a big, unguarded swing for a network drama built around a con artist and a mermaid, and it mostly earns it — less because the mythology is airtight, and more because Joon-Jae and Sim Chung’s chemistry never once looks like it’s running on autopilot.