Double Crossed is a crossover of two of Allie Carter's hit series, Heist Society and Gallagher Girls. Two strong teenage "professionals" meet during a elegant party which has gone bad. Macey, a high society CIA-like professional from Gallagher Girls, finds herself a hostage at a elite dinner party with Hale, Kat's friend from Heist Society. While using all their strong skills sets, this groups of teenagers are able to save the evening and prove who the person is behind the crime. I enjoyed the story, but as on all novellas, it was too short. Allie Carter has included the first few chapters of each series which introduces you to the characters and the story lines. I have not read the Gallagher Girls series, but love the Kat and Hale's story in Heist Society. Even though Allie is ending the Gallagher Girl series, I am looking forward to diving into it while picking up the third book of the Heist Society. I will say, I hope Allie will follow through with the cliffhanger she left off in this book.