In 1952, Mitsuki waits for the streetcar with her lover Toichiro in Hakodate, Japan. This is the last time Mitsuki sees Toichiro. When Mitsuki boards the streetcar, Toichiro has vanished.
50 years later, Megumi runs a company in Tokyo, but she is betrayed by her lover. Megumi returns to Hakodate and moves in with her mother Mitsuki, who doesn't have many days to left to live. One day, Mitsuki asks her daughter to find Toichiro. Megumi begins to read through a hundred of their love letters. Koga, who Megumi meets at a bar, says that Toichiro orchestrated his own disappearance. Megumi continues her search as the truth of Toichiro's disappearance begins to come out. ~~ Adapted from the novel "Tazunebito" by Shiho Tanimura