One

Would you remember a promise you made ten years ago? This central question of promises, of memories, and of love -- this is the question that plagues a group of friends in Japan: a young and very talented girl who is well on her way to becoming a superstar, an average guy with an eye for beauty, and a girl from their past. She has returned from a trip to the USA because she remembers a promise they all made ten years ago.. but ten years is a long time, and memories are easily forgotten. Who knows what could come from this reunion...

For Aizawa Yuuichi, returning to the town where he spent his childhood has been an unusual affair. Yuuichi, it seems, has forgotten his memories of the past, including encounters with several young ladies who would love nothing more than to see him again. As the days pass, flickers of the past began to surface, revealing more and more of the dark events that once came to be. As the reuniting continues, Yuuichi soon starts to realize that his past may be far more complex than he once believed it to be...

As children, Ken, Yuki, and Hiyori were the best of friends. But like a flash, the companions were torn apart when Hiyori mysteriously vanished without warning. Now, as young adults, Ken and Yuki are in for a surprise when Hiyori returns, but in a manner that they would never think to expect -- falling out of Ken's closet? And what's worse is that she appears to be a ghost! Armed with newfound curiosity, the trio try to remember what happened in their past, and why their long-lost friend has suddenly reappeared...