Memories loom large in Alison Gaylin’s second Brenna Spector novel, Into the Dark, as her heroine, a New York PI, suffers from a rare condition called hyperthymestic syndrome, causing her to remember everything that’s happened around her since she was 11—sights, sounds, smells, conversations, everything. It’s a blessing, as she’s a veritable treasure trove of knowledge about certain events, and a curse, as she often effectively begins to relive past events unless she’s able to apply a coping technique. Her personal history figures prominently here, as the seductive murmurings of a missing Internet performance artist, “Lula Belle,” conjure memories of her sister Clea, who went missing decades prior. Hoping she may be reunited with her long-lost sibling, Brenna takes the case, doggedly pursuing leads even after she realizes her well-being, and the well-being of those around her, may be threatened by doing so.

Spector is a great character, and Gaylin exploits her unique condition effectively, cannily avoiding making it into the primary focus of her series. Spector’s surroundings and supporting cast are well drawn, allowing readers instant access into her world. The fact that the case is so personal only makes the book more compelling, as Gaylin manages to convey a sense of urgency throughout her carefully crafted narrative.