Neither Carter Cho nor Mariana Pineda knows exactly what the Hawke accelerator is accelerating. But whatever it is, it shakes the whole universe apart every four days and resets. Initially, Carter is alone in his awareness of the looping, and he’s bored with it all. Until he manages to pull Mariana into his awareness of the loop. As history repeats all around them, Carter and Mariana occupy a little bubble of two, a bubble that explores what’s gone wrong and how to fix it, even as they tentatively reach towards a relationship that neither of them could have expected. Just as they near a solution, Carter slips out of their bubble. Mariana chooses to sacrifice everything to get him back—hopefully saving the world along the way. VERDICT Combining the sweet redemption and understated romance of Groundhog Day with the multiple explosive resets of Edge of Tomorrow, this novel from Chen (Vampire Weekend) loops its way through a charming story about opposites attracting, the human ability to reset expectations and emotions against all the odds, and the power of one woman willing to make a big sacrifice for a small change that might just save the universe.