Limited wish

In the summer of 1986, Nick Hayes--a prodigy, boy-genius, cancer survivor, and even a time travel dabbler, and student at Cambridge University--has begun working with the renowned mathematician Professor Halligan. When he meets a stranger who seems nevertheless familiar, Nick begins to fear his activities have created a disruption in time. Now, Nick, his ex, Mia, and new fellow student Helen must work together to avert the apocalypse of time running out--literally.