What if memories could be transplanted along with a heart?Before Bay Area 17-year-old Chloe collapsed while running and learned about her congenital heart defect, she was a competitive senior with her eyes set on college. Life post–heart transplant is completely different, and Chloe can't seem to connect to her old life. Inexplicably drawn to taking up surfing, she finds herself falling for Kai, her enigmatic surf instructor. But she can't ignore the constant, haunting nightmares and surreal, fragmented memories that inexplicably bombard her. A lifelong fan of science, and especially multiverse theories, Chloe finds herself hoping that cellular memory, the ability to store memories in cells outside the brain, is true. Because she's almost 100% sure her anonymous heart donor gave her more than just an oxygen-pumping organ. What begins as a predictable rom-com veers into alternate/parallel universe science fiction, with each layer casting more doubt on Chloe's reliability as a narrator. A slow start with repetitive exposition gives way to a page-turning finale. SF newbies may find the conclusion thought-provoking even if the puzzle pieces of Chloe and Kai's relationship don't always quite click into place. Chloe is White and Kai, who is from Hawaii, is biracial (Japanese/White).Romance and quantum physics intertwine in this frothy introduction to multiverse SF. (Science fiction. 14-18)