MechatroWeGo are robots that kids can pilot and operate. Satoru pilots an old WeGo that his grandmother gave to him as a gift. When the kids gather in their secret base to race their WeGos, Satoru can't take the first step. Satoru's classmate Akira invites him to race again. This is a story of a boy and his robot, set in a seaside town in the near future.

Following the events of Satsujin Kousatsu (Zen), Shiki Ryougi has been in a coma for two years due to a traffic accident. When she finally awakens, she has no memories of her past and is plagued by a profound loneliness. Even stranger, she notices dark lines encompassing the things around her, and if she touches them she can disassemble the object—something which completely terrifies her. Her friend, Mikiya Kokutou, enlists the help of Touko Aozaki, a mage who can help Shiki understand what her eyes—the "Mystic Eyes of Death Perception"—are truly capable of and how to use them properly. 

Finally, the day of Mai's high school graduation has arrived. While Sakuta eagerly waits for his girlfriend, an elementary schooler who looks exactly like her appears before him. Suspicious, and for all the wrong reasons... Meanwhile, Sakuta and Kaede's father suddenly calls, saying that their mother wants to see her daughter. She was hospitalized because Kaede's condition had been too much for her to bear, so what could she possibly want now?

What will it take to make her wish come true? After a draining December, Sakuta is quickly nearing the end of his second year of high school. Since Mai is a third-year student, they don't have much time left together before graduation rolls around. Meanwhile, his sister, Kaede, is slowly but steadily venturing outdoors again. Just as she begins to find her footing, she announces her most ambitious goal yet—attending her brother's high school! Sakuta knows better than anyone how difficult this will be for Kaede, and he's ready to support her however he can. He's just not sure if that's what's best for her...or what she really wants...