Bela and Lizzy, the dominant megalodon siblings from Angel's brood, have escaped the Tanaka Institute to roam the Salish Sea in British Columbia. While Jonas Taylor and his friend Mac attempt to either recapture or kill the "sisters," Jonas' son, David, embarks on his own adventure, motivated by revenge. Having witnessed his girlfriend's gruesome death, David has joined a Dubai prince's ocean expedition, tracking the 120-foot, hundred-ton Liopleurodon that escaped from the Panthalassa Sea.

Eighteen years have passed since Jonas Taylor last crossed paths with Carcharodon megalodon. Now a middle-aged father of two, he is overwhelmed by mountains of bills and the daily strife of raising a family. But life is about to change. A Hollywood television producer wants Jonas to join his new survival series: Daredevils. For the next six weeks, two teams of crazy daredevils on a South Pacific Ocean voyage will try to outperform one another in front of the cameras.

Book six in the best-selling Meg series picks up after Meg: Nightstalkers with David Taylor in the Salish sea, attempting to locate and rescue any surviving Megalodon pups before a local fisherman slaughters them. Meanwhile, Jonas is coerced into joining an expedition into the Panthalassa sea in search of a prehistoric predatory species possessing liver enzymes that can cure cancer.

Loch Ness holds secrets, ancient and deadly. Does a monster inhabit its depths, or is it just myth? Why, after thousands of reported sightings and dozens of expeditions, is there still no hard evidence? Marine biologist Zachary Wallace knows, but the shock of his near-drowning as a child on Loch Ness have buried all memories of the incident. Now, a near-death experience suffered while on expedition in the Sargasso Sea has caused these long-forgotten memories to resurface.

Its appetite is ravenous. Its teeth scalpel-sharp. Its power unstoppable as it smashes the steel doors holding it in a Monterey, California, aquarium. The captive 20-ton Megalodon shark has tasted human blood, and it wants more.