Scooby-Doo! Curse of the Lake Monster (2010)

Storyline:
Scooby-Doo and the gang are on the case when a mysterious lake monster starts scaring the guests at a summer resort in Erie Point, where Fred, Daphne, Velma and Shaggy have taken on seasonal jobs to pay for a barn they accidentally burned down. But in addition to sneaking suspicions, there's some romance in the air.