Nana Yamashita has been an absolute trainwreck ever since her girlfriend went missing nearly a year ago. She can barely remember who she was before that fateful morning when she woke up and realized that something had gone horribly wrong. Stuck in the memories of her old relationship, she can't move on. She hardly sees the point of breaking the monotonous loop of her tepid life in California when everything good about living has been taken away.

But her mother's new marriage to a businessman in Tokyo forces her to snap out of it. Before she can catch her breath, she's thrust into the eccentric world of the Watanabe family and forced to befriend her new sister. Too bad the only daughter of the Watanabe family isn't interested in being nice to her. It doesn't help that she reminds Nana of her missing girlfriend.

When new details about her ex's disappearance are uncovered, Nana must choose between staying in the past or moving forward into an uncertain future.