''Winter Sonata'' refers both to the hit South Korean SoapOpera and its AnimatedAdaptation. It was broadcast on Japan's NHK and has been a major part of the 'Korean Wave' both there and throughout Asia.
The story revolves around the fated love between pretty Yuujin and brooding Joonsang. They first met when Joonsang transfers to her high school, with the secret intention of discovering the identity of his biological father, whose name his mother has hidden from him to the extreme point of removing it from his memory. Armed only with an old, damaged photo of his mother standing between two men (one of whose face's is burned), Joonsang is looking for one or both of those men, as possible candidates. He comes to believe that the father of one of his classmates, Sanghyuk, is also his father (possibly making them half-brothers); to complicate matters, Sanghyuk is Yuujin's friend-zoned best friend. Meanwhile, Chae-lin, the class AlphaBitch, decides that she will conquer Joongsang's heart.
Despite (or rather because of) their different personalities, the free-spirited Yuujin and aloof Joonsang fall in love, to the chagrin of Sanghyuk and Chae-lin. But during a melodramatic visit to Yuujin's home, Joongsang discovers that she has a complete copy of the photo Joonsang has, with the burned face revealed to be the late father of Yuujin (possibly making Yuujin his half-sister). Now dubious about his conclusions, he decides he confess everything he knows to Yuujin on New Year's Eve, but before he can meet her, he is hit by a truck. The next day, the school receives news that Joonsang has died, leaving both Yuujin and Chae-lin in despair.
Ten years later, Yuujin (now an architect) and Sanghyuk (a radio host) are engaged to get married. But the night of their engagement dinner, Yuujin mets a man who looks eerily similar to the late Joonsang, and becomes so shocked and distraught that she fails to go to the dinner. The mysterious man happens to be Chae-lin's new boyfriend, an American-raised architect named Ming-hyun. Yuujin becomes greatly troubled, exacerbated by a series of coincidences constantly causing her and Ming-hyun to cross paths, and she fears that she is falling in love with him. Although the very open and easygoing Ming-hyun is nothing like the serious, brooding Joonsang, there's just something about how both men are so alike that Yuujin's heart simply can't let it go...
* AlphaBitch: Chae-lin.
* BastardBoyfriend: Sanghyuk seems to love alternating between piling the guilt on Yuujin and pressuring her through her mother, not to mention [[spoiler:assaulting his fiancee in a hotel room]].
* BelligerentSexualTension: Joonsang
** [[spoiler:Revised Ending: The anime ends with a live-action scene of Joonsang and Yujin's wedding. Also note that while Joonsang went totally blind in the original series, it's hinted that Joonsang didn't in the anime.]].
* BetaCouple: Two of Yujin's classmates get married halfway through the anime.
** PairTheSpares: [[spoiler:Sanghyuk and Chae-lin.]]
* BrotherSisterIncest: Why Mi-Hee, Joonsang's mom, is against him and Yujin hooking up.
* ChildhoodFriendRomance: With Sanghyuk.
* DoggedNiceGuy: Junkyuk, who is very cute for a psychic veterinarian.
* EarnYourHappyEnding: Yujin, and how!
** Ironically subverted by Joonsang.
* EvilMatriarch: Mi-Hee, to the extent to [[spoiler:brainwash her amnesiac child to make him forget his unhappy childhood, and his probably incestuous romantic interest]].
** [[spoiler:TheAtoner: After Joonsang's mom realized everything she did caused more harm than good, she went into exile in an asylum. Sanghyuk's father had to coax her out of the asylum.]]
* GeneHunting: The reason Joonsang went to his mother's old town and high school.
* GenerationXerox: Joonsang' mom and Yuujin and Sanghyuk's dads formed a love triangle very similar to the one their descendants have.
* HeroicBastard: Joonsang
* IncestIsRelative: Who is the real father of [[spoiler:Joonsang? Yuujin's or Sanghyuk's?]] Does it really matter?
* KarmaHoudini: Guess...
* LoveTriangle: ''Oh boy'', where do we start!?
** TriangRelations Type 4 --> Type 10
** [[spoiler:SiblingTriangle]]: Turns out [[spoiler:Joosang and Sanghyuk are half brothers.]]
** [[spoiler:TwoPersonLoveTriangle]]: When Yuujin falls in love with Min-hyung, she isn't sure if it is for himself, or because he looks too much like dissapeared Joonsang. [[spoiler:Turns out Min-hyung is an amnesiac, post brainwashing Joonsang]]
* LukeYouAreMyFather: Joonsang does this[[spoiler:to Sanghyuk's dad, Jinwoo]] twice. He doesn't invoke this back in high school, but after the BrotherSisterIncest fiasco with Yujin, he demands a DNA test.
** Foreshadowing: Every time Jinwoo brings Joonsang to the hospital, he gets questioned whether he is Joonsang's father.
* MeaningfulEcho: Joonsang gets into a truck accident, which leads to him forgetting Yujin. Later, as Minhyung, he gets into another accident. [[spoiler:He's safe, but the shock brings back all of his memories of Yujin]].
* MissedHimByThatMuch: Yujin misses her engagement party while wildly looking for someone who looked like her first love.
* RaceForYourLove: Practically every time someone goes to the airport.
* SceneryPorn: The Pilot of the anime contained copious amount of it. The original series wasn't lacking of that aspect, either.
* SnowMeansDeath: [[spoiler:Joonsang's Disney Death]].
* SuspiciouslySimilarOutfit: Che-lin tricks Yoo-jin into wearing the same dress at the same party, then claims it's because her friend is jealous and mentally ill.
* TraumaInducedAmnesia: Joonsang
* TroubledButCute: Joonsang
* SleepCute: That's how Yuujin and Joongsang first met.