Mystery-book aficionado Birdie Lindberg was raised in isolation and homeschooled by strict grandparents. But her solitary world expands when she takes a job the summer before college, working the graveyard shift at a historic Seattle hotel. The hotel's charismatic young van driver shares the same nocturnal shift and patronizes the waterfront Moonlight Diner where she waits for the early morning ferry after work. Daniel also shares her appetite for intrigue, and he's stumbled upon a real-life mystery: a famous reclusive writer, never before seen in public, might be secretly meeting someone at the hotel. To uncover the writer's identity, Birdie must come out of her shell and discovers that most confounding mystery of all may be her growing feelings for the elusive riddle that is Daniel.