The World Tour team are in a clean body of water when some giant creature passes beneath them. They get to shore and find a town – Elisa goes to call Matt Bluestone to notify the gargoyles and finds they're at Loch Ness in Scotland. Elisa fails to leave a message with Matt and they return to the Loch to continue their journey, but see a tour boat attacked by famous "Loch Ness Monster," which then knocks their own boat over. Then they see a giant mechanical "monster" emerge, pursuing the real Nessie. Angela is knocked out and as Goliath goes after her, he sees the mechanical version grab her.
The mechanical creature returns to an underwater docking bay where it turns out that Dr. Sevarius is in charge of the operation. Sevarius is intrigued by the mention of gargoyle and the capture of Angela. Angela is left in the Grotto, where there is a young version of Nessie imprisoned. The young Nessie, dying, recovers thanks to Angela's presence, while Sevarius conducts an analysis of her DNA. Elisa goes to search for the submarine base during the day and spots men out shopping. Sevarius reveals to Angela that Goliath and Demona are her parents. Goliath, Elisa, and Bronx enter the base but are imprisoned, while Sevarius takes Angela out in the sub and uses the small Nessie (with an electronic tracking collar) to lure in the big one. Goliath escapes, setting off an explosion in the gunfight that floods the base. They escape in a mini-sub and give pursuit. Goliath gets to Angela and gives her a rebreathing mask so she can get away. They take the collar off of the smaller Nessie – Sevarius tries to taser it and both creatures attack his sub. Sevarius plunges into the depths and the two creatures plus their entire herd bid the gargoyles farewell.