Ichiro Kuga is a manga artist struggling to support his two young siblings, and he's in need of an assistant. Shiori Goshiki wishes to become that assistant, but her background is unusual in more ways than one.

Shiori and the Kugas finally make it to the zoo, and it's Shiori's first time visiting one. It's also her first date with Ichiro since they officially became a couple, and there are unexpected hurdles to clear.

Shiori goes with the Kugas to visit their father's grave, as her relationship with Ichiro slowly deepens. When she comes down with a fever, it becomes Ichiro's turn to help her get back on her feet again.

It's time for the Christmas party, an annual tradition at Hiiragi Apartments. Shiori continues to grow closer to Ichiro, but she also spends time with some of the other friends she's made since her arrival.

Some amazing New Year's luck sees Shiori and the Kugas take a trip to a hot spring resort. But Shiori's mother Miyako is growing impatient, and she begins taking steps to get her daughter to return to the island.

Shiori's parents track her down and confront her in person about her situation, which she and Ichiro now must find a way to explain. Can they convince them to let her stay, and is there any way to annul the Engagement Pact?

The fated day arrives, the day when Ichiro and Shiori will annul their Engagement Pact. But there's a risk their feelings for each other will vanish in the process, and there's no way to be sure without performing the ceremony.