Thalia Throne's summer plans are simple. She's going to work part-time at her aunt's diner--a popular hangout for teenagers like her--and also have a touch of fun. The fun factor only increases when Thalia's long-distance best friend, Sophie, arrives in town from Scotland. But instead of adding to the fun, Sophie's sudden appearance causes nothing but trouble.Shockingly, Thalia comes face to face with trolls like out of some horrible fairy tale. The trolls try to kidnap Thalia, but Mike rescues her. He's a friend who now claims their lives are tied together by destiny. Sophie is somehow involved, too, and in just as much danger as Thalia and Mike. The three friends find themselves ducking monsters at every turn.It turns out Thalia is the key to bringing The Dark One back to the mortal world. Minions of The Dark One will do anything to get to her first, so she'll have to not only lean on her friends but also her own bravery to get out of this one alive--especially as her feelings for Mike take a romantic turn. This summer could cost Thalia her life ... or be the season of dreams coming true.