Since You’ve Been Gone (by Morgan Matson)

I love a good summertime YA in the summer! Our protagonist Emily only has one friend, a manic pixie dream girl named Sloane. When Sloane disappears, leaving Emily a list of tasks to push her out of her comfort zone, she decides to try the tasks in the hope of finding Sloane again.

Emily is likeable in her willingness to slowly come out of her very hard shell over the course of the summer. The friendships that build over the course of the novel (and the romance too, of course) are charming. Weirdly there are a lot of typos in the Kindle edition. But I enjoyed this nevertheless.