Sixth graders Anika Veerkar, Benicio "Benny" Flores, and Libby Abrams live a short drive from a small lake, but they've never been swimming in it. It's closed off as a "Superfund" site, a mysterious phrase they've never heard elsewhere. When Benny's out-of-town uncle brings him fishing gear as a present, only to find out no one is allowed to fish in the lake, the friends determine their next big question to explore: Why is the lake off-limits? As the friends interview their neighbours and explore their community's history, they'll find that not being able to swim or fish in the lake might actually be a good thing. Anika, Benny, and Libby are neighbourhood friends -- and known to be relentlessly curious. They're always asking questions, and their interest in sharing the answers has led them to start an online newsletter. Encouraged by their parents, they venture out into the community to investigate the most engaging mysteries.