They Both Die at the End meets You've Reached Sam, in this heart-stopping speculative young adult novel from New York Times bestselling author Robbie Couch that explores all the different ways love can live on after tragedy.It's been a year since eighteen-year-old River Lang's best friend died in a car accident. And every day since, he's had to pass by the depressing billboard that appeared as a result: a texting and driving PSA that reduces Dylan to a cautionary tale and River to the best friend of the dead kid at school. Dylan was so much more than a statistic, though, and River hates that everyone in town seems to have forgotten. When he's caught improving (a.k.a. vandalizing) Dylan's billboard, River is blackmailed into joining the Affinity Trials--a research study that's observing teens who are "struggling socially." But as soon as he arrives, River's social struggles only worsen as he's thrown together with the last person he wants to spend an entire week with: his ex-best friend and Dylan's former girlfriend, Mavis, who's the only one who knows the truth about the night Dylan died. During the Trials, River befriends a charming quarterback named Nash, and it doesn't take long for romantic feelings to start bubbling to the surface. But so do bizarre developments within the Trials that make him wonder what researchers are actually studying while monitoring his every move. And when suspicions lead him to a bombshell discovery, River will have to decide just how far he's willing to go for another chance at first love.