Since You've Been Gone by Morgan Matson { Goodreads } Published by Simon & Schuster in 2014 Hardback edition; 449 pages { BookDepository } Emily and Sloane are best friends. Inseparable. Yet, when the summer kicks off Emily is up for a very unpleasant surprise: Sloane is missing. She left without a note, without a call and Emily doesn’t know why. One day, however, her mother tells her there is a letter and within, a list containing 13 missions that Sloane wants Emily to complete. She doesn’t know how she’s gonna do it because while some of them are very easy (like breaking something), others are a bit more complicated (did someone say skinny-dipping?). Despite all that Emily feels the need to complete the list since she believes will be the only way to get her best friend back.