Blood Gems by Lucas Flint

A field trip to the beach quickly turns into a nightmare when cyborgs attack Bait, Switch, and their classmates. The nightmare becomes even worse when two new and dangerous supervillains kidnap Switch under the orders of their master, a mysterious man known as the Collector whose true goals are an enigma.

To rescue Switch, Bait must seek the aid of his supervillain father, Tsunami, who will be able to help him locate the Collector. But Tsunami has plans of his own and Bait is not sure he can trust him, yet he must if he is to save his sister.

But even if Bait saves Switch, he may be unable to stop the Collector's real plans.