"I let my guard down, I trusted him. Big mistake." But when Chloe finds a box filled with letters documenting some of their most important moments as a couple, she starts to think. Was it my trust that was lost? Or was it his?

An 11 year old girl, Mackenzie Ziegler, has a brain tumor and has one year to live. she writes in her diary and lives life the best she can. Is her death-date accurate? Will she make it?