Blue Like Friday (by Siobhan Parkinson)

This book manages to be both funny and heartwarming, without ever being cloying. This is mainly due to the sweet friendship between offbeat Olivia and even more eccentric Hal. ("Hal is like a little white mouse with a twitchy nose. You can't help liking him, even if the twitch drives you mad.") Readers may have a hard time believing how worked up Hal and Olivia get over his missing stepfather. It's also sort of surprising that Olivia waits several days before telling her mother that Hal's mother has disappeared, especially since Hal is so distraught over it. Kids may find the answers to both missing-person crises a bit anticlimactic, though the easy answers -- and Hal and Olivia's inability to sort them out -- do say something about their childlike thinking. It might have been worthwhile if Hal's synesthesia had worked more into the plot. As it is, his condition is more of a marker of just how unusual he is.

But, these are just small criticisms. Readers will be touched by how vulnerable Hal and Olivia can be with each other. In one scene, he bursts into tears in front of her because he is so relieved his mother is OK; in another, she tells him she loves him, knowing he wasn't going to worry that she was "proposing to him or anything." In the end, it's impossible not to like Hal and Olivia, and to be moved by their sweet, small story.