Shortly after the death of William Wallace, a group of Knight Templars bring his heart to Loch Ness with the intent to hide it in a cavern.

Hundreds of years later Scottish-born Zachary Wallace has returned to Loch Ness to reconnect with his father Angus, who has been accused of murdering wealthy land developer Johnny Cialino over money owed.

Hoping to find giant squid, the expedition instead resulted in the loss of an expensive submersible and its pilot after they were attacked by an unseen creature Zachary identified as the source of the mysterious phenomenon "The Bloop".

During his investigations into the loch, Zachary learns that True's father Albin is part of the Black Knights and that his former boss David, who was quick to blame him for the Sargasso incident, is going to lead teams of monster hunters in an expedition to find and capture Nessie.

David hires Brady and her boat as his mode of transport around the loch, something Brandy uses as a means to get even with Zachary for not being open with her about his phobias and feelings.

Eventually Zachary realizes that the monster is a distant cousin and predecessor to the Anguilla eel, which was trapped when bridge construction damaged the Black Knights' gate many years ago.

Zachary is able to clear the gate blockage successfully but is ultimately forced to battle the monster using his ancestor's sword, which he discovers nearby.

[9][10] An audiobook adaptation narrated by P. J. Ochlan was released in 2016 through Blackstone Audio,[11] and in 2018 Alten published a re-edited collector's edition of the novel that was accompanied by photos, maps, 3D images, and a report on the Loch Ness Monster.

[1][2] A third book, The Loch: Heaven's Lake, will be published in audiobook format in 2024 or later through Blackstone Audio after a delay of 2 years.