They Both Die At The End

"On September 5, a little after midnight, Death-Cast calls Mateo Torez and Rufus Emeterio to deliver some bad news: they are going to die in less than twenty-four hours. Mateo and Rufus are total strangers, but, for different reasons, they're both looking to make a new friend on their End Day. The good news is there's an app for that. It's called Last Friend, and through it, Rufus and Mateo meet up for one final epic adventure-to live a lifetime in a single day."