What a Whopper

Struggling young writer Tony Blake is served an eviction notice by Mr. Slate from his rented room in a Chelsea house. He shares the house with other artists, including the abstract painter Arnold. Tony is facing financial difficulties and is desperate for attention for his rejected book about the Loch Ness Monster.

Tony hatches a plan to generate interest in his rejected book by faking a sighting of the Loch Ness Monster. He and his friend Vernon create a fake monster using electronic effects and photographs it in the Serpentine, startling a tramp nearby. The scheme aims to attract media and public attention.

Tony, Vernon, and Vernon's girlfriend Charlie decide to visit Scotland with the intention of furthering their ruse of the Loch Ness Monster. They drive a second-hand Rolls-Royce hearse through scenic roads, along the way picking up a young French hitchhiker named Marie.

During their journey, the group is pursued by Charlie’s dipsomaniac father, adding a layer of tension and humor to their trip. The chase causes additional complications as they plan their presentation of the monster.

Tony and his friends arrive at a Loch Ness inn, where the landlord Harry Sutton is secretly hiding dozens of poached salmon from the police. The locals are eager to see the monster and become excited when Vernon secretly broadcasts a roar, convincing them of the creature's existence.

The inn quickly becomes packed with press and tourists, eager to witness the monster. Tony promises to deliver a photo, but he fails to produce the expected evidence, causing the crowd's enthusiasm to wane and skepticism to grow.

While the media attention continues, Vernon and Charlie decide to get married, and Marie develops romantic feelings for Tony. Meanwhile, the poached salmon are accidentally loaded into a police car, complicating the situation further.

Tony and Vernon craft another fake monster to rekindle interest in the story, only to discover that several locals have also made their own fake monsters to attract business. The deception begins to unravel as the secret speaker is discovered.

The locals realize they have been tricked by the fake monsters and discover Vernon’s hidden speaker broadcasting roars. The anger surges as the truth about the deception is exposed, leading to distrust among the community and visitors.

An angry mob starts chasing Tony and Marie after the deception is revealed. The duo attempts to escape by rowing across the loch, desperate to evade the furious locals and media.

As Tony and Marie try to escape, the real Loch Ness Monster rises from the water, shocking everyone. The sighting confirms the legendality of the creature, ending the film with an unexpected twist.