Aspiring costume designer Katie gave up everything in her divorce to gain custody of her fearful, faithful rescue dog, Barkimedes. While she figures out what to do next, she heads back to Florida to live with her grandmother, Nan.

But Katie quickly learns there's a lot she doesn't know about Nan--like the fact that in her youth Nan was a mermaid performer in a roadside attraction show, swimming and dancing underwater with a close-knit cast of talented women. Although most of the mermaids have since lost touch, Katie helps Nan search for her old friends on Facebook, sparking hopes for a reunion show. Katie is up for making some fabulous costumes, but first, she has to contend with her crippling fear of water.

As Katie's college love Luca, a documentary filmmaker, enters the fray, Katie struggles to balance her hopes with her anxiety, and begins to realize just how much Bark's fears are connected to her own, in this thoughtful, charming novel about hope after loss and friendships that span generations.