Simon and Nova swam through the dense seaweed. The water bubbled, splashed and frothed around them, but the sea monster was faster than they were. It had already caught up with them. Nova could sense it nipping at her feet. In just a second or two, the sea monster would devour them!

The twins started their semi-secret helper agency when they were utterly bored one balmy summers day. After their first mission, they understood that fantastic creatures and magical places are just around the order if you are just daring enough to look. But the second case of the Helper Agency proved to be much more difficult than the first one. Nova and Simon follow the mysterious Julian to the bottom of a deep lake, where they discover all the mermaids and aquarians have been cursed. The Helper Agency has to help them break this bad spell. But it isn't all that easy when, at the same time, they also have to fight a nasty sea monster and a trio of wicked witches.