Fumiya Ikegami, a salesman, and Ritsu Okusawa, who is an illustrator, meet in an old coffee shop, fall in love, and lead a happy cohabitated life. However, Ritsu is a workaholic and Fumiya is a private person, and their lives gradually begin to diverge. One winter day, Ritsu leaves home after a quarrel, meets an unfortunate accident and loses consciousness. Turns out that he has lost all memories of Fumiya so far.
Not wanting to cause Ritsu any emotional distress, and wishing to start over, Fumiya withholds the fact that they have been dating from Ritsu and they keep living together as “roommates". However, Ritsu asks Fumiya to take him to a familiar place in order to regain his memory. Although Fumiya is unwilling, the two still begin a “journey" to retrace the steps of their relationship. The coffee shop where they first met, the park where they always took walks, the places they traveled together before... Fumiya's mind is filled with bittersweet memories of their time together. Meanwhile, Ritsu finds himself gradually becoming attracted to Fumiya...
Will Ritsu succeed to get his memory of Fumiya back? What should the relationship between Ritsu and Fumiya be named?