In 27 Days by Alison Gervais

Hadley Jamison is shocked when she hears that her classmate, Archer Morales, has committed suicide. She didn’t know the quiet, reserved guy very well, but that doesn’t stop her from feeling there was something she could have done to help him.

Hoping to find some sense of closure, Hadley attends Archer’s funeral. There, Hadley is approached by a man who calls himself Death and offers her a deal. If Hadley accepts, she will be sent back 27 days in time to prevent Archer from killing himself. But when Hadley agrees to Death’s terms and goes back to right the past, she quickly learns her mission is harder than she ever could have known.

Hadley soon discovers Archer’s reasons for being alone, and Archer realizes that having someone to confide in isn’t as bad as he’d always thought. But when a series of dangerous accidents starts pushing them apart, Hadley must decide whether she is ready to risk everything – including her life – to keep Archer safe.