Below by Meg McKinlay (review)

The small Australian town of Old Lower Grange drowned the day Cassie was born, buried underneath a newly developed reservoir as the town recreated itself nearby as New Lower Grange. Cassie has always been obsessed with the old town, site of so much of her family's history, and when she's had enough of swimming in the town pool ("It was the seven Band-Aid swim that finally sank me") she starts sneaking into the reservoir over Old Lower Grange to swim there. The receding water levels allow her and her classmate Liam to dive down and reach bits of the old town, but what they find is strange—an expensive car that would have been brand new at the time secreted in an outlying shed. The mayor's new determination to keep people out of that side of the reservoir, however, claiming dangers that Cassie and Liam know aren't there, may interfere with their sleuthing. McKinlay neatly weaves together an offbeat realistic tale and an accessible mystery, writing with calm, easygoing accessibility and a touch of poetry as Cassie and Liam traverse the waters to look for a past they never lived. Cassie is credibly haunted by Old Lower Grange, and the flooding of the past seems both marvelous and heedless. The mystery is within plausible bounds, and it leads to a secret that's tragic but ultimately freeing. This makes the beautifully eerie seem everyday, an impressive feat that makes for an easy booktalk and an inviting read.