Berk is busy preparing his master's breakfast - from worms and other vile concoctions, when a strange yellow creature comes out of the trap door in the kitchen floor and eats the breakfast, closely followed by a large Big Red Thing which chases Berk until Berk hides behind a mirror - the ugly monster gets a nasty shock and retreats down the trap door.

Prompted by his master's demands for breakfast, Berk takes the yellow creature, which has eaten everything and fallen asleep, and feeds it to his master as Chef's Special...

Berk is trying to put up some shelves for his master and is using Boni as a prop to hold up the shelf. Looking for some more wood, Berk opens the trap door, but a huge octopus-like creature emerges with writhing arms and creates havoc in the kitchen.

Berk is instructed to go and see to the garden. He goes out to feed the plants, especially Thort, his master's favourite vegetable. Returning to the kitchen he opens the trap door to get some worms for dinner, but a swarm of large bees come out and sting him. Berk runs out to the garden followed by the bees, who are eaten by Thort. When the Thing Upstairs shouts for food, Berk suggests a salad ...

Berk, Boni and Drutt go down to the swamp outside the castle to do some fishing. Boni is moaning because he finds it boring, but Berk has left the trap door open and he is soon surprised by an enormous pink monster who creeps up behind them. Berk is so frightened he falls into the swamp, only to find the monster is friendly and wants to join in...

Berk is cooking again, when something invisible comes out of the trap door and starts throwing things about. Berk scores a direct hit in retaliation with some yellow goo and the little creature - Bubo - becomes visible and bright yellow. When Berk eventually catches the naughty Bubo, he finds a hole in the top of his head, blows him up like a balloon and lets him off into the air and lets him drop back down the trap door.

Something large and black with "lots of legs" comes out of the trap door and scuttles off down the corridor, but Berk won't believe Boni. He goes in search of it and finds a tiny spider, thinking it must be Boni's monster, but just then the enormous black spider drops down in front of him, wraps him in thick green web and chases him into the kitchen. Drutt spins the spider up in his own web and Berk is able to push it back down the trap door.

Boni is bored, but Berk doesn't have time to talk to him. Then Rogg appears from the trap door and takes Boni out 'to play' on top of the castle ramparts. Boni talks and talks and bores Rogg until he falls off the castle on top of Berk, who has come in search of Boni. Boni is left talking to himself...

Berk and Boni are going through things in a room that's been left untouched for a long time. Berk finds an old book of spells and reads one out, summoning up the 'Ghostly Ghoulies' ... They rush back to the kitchen to find the trap door thumping open and shut and ghoulies floating about the place. To make them go away he has to read the spell backwards...

The Thing Upstairs has a cold, so Berk makes him some of his special medicine. Meanwhile, a 'horrible green gobby lump' comes out of the trap door and drinks all the medicine, with strange results. As Berk drags the little green thing back to the trap door, he finds the creature's mum has come out too - a large yellow lump. Berk, Boni and Drutt all end up with colds.

Berk is trying to nail the trap door down, but it's no good - a large peculiar looking Thingy comes popping up and changes Berk, Boni and Drutt into all sorts of different shapes, before eventually disappearing again, leaving them back to normal.

Berk goes to sleep but something horrid emerges from the Trap Door and kidnaps Boni. Berk goes down to rescue him. This is one of two episodes which is revealed to be a dream at the end, the other being "Moany Boni".

Bubo, the spout-headed troublemaker from "Gourmet's Delight" is back and he's pushing a distressed Boni about the workroom on his trolley. He takes Boni out to the swamp and starts beating him with a stick. Berk and Drutt arrive, lured by the sound of Boni's moaning that Berk had mistaken for singing. Bubo pokes Berk in the keister with the stick, sending the former straight into the bog, and Drutt tumbles in as well. They both get back out and Berk throws Bubo into the swamp. The three friends head for home, sure they've seen the last of Bubo, who can be seen swimming for shore.

The Thing Upstairs has toothache so Berk goes to sort it out. Drutt wedges open the trap door so he can eat some worms, inevitably releasing a hungry slug thing which decides to eat him instead. This episode is centered on Drutt trying to escape from the creature.

A noisy little thing has escaped and Berk must catch it before it wakes the Thing Upstairs.

Whilst cleaning out his cupboard Berk finds an old radio and all the monsters (past and future) emerge from the trap door to dance to the theme tune. This episode acts as more of a music video of the series.

Rogg returns and eats all the garbage; he then causes trouble by going up in the lift to the Thing Upstairs's room.

Something horrible escapes and lays its eggs. Little things hatch quickly only to pop almost immediately, causing havoc for poor Berk.

Berk is trying to take a photograph of Boni and Drutt but is interrupted by a green bat, which he and Drutt pursue around the cellar. Ultimately, Berk's camera photographs them all, and the flier escapes into his master's bedroom.

Berk is taking everyone on a picnic but has to scratch the Thing Upstairs before he leaves. While he's gone something pulls Boni down the trap door. This episode is centered on Boni and his experiences through the trap door caverns then the swamp.

Whilst everyone is asleep four near-identical greedy things emerge and raid the kitchen, causing a mess.

Berk makes some medicine for his headache, but after drinking it he turns into a horrible monster.

Something with a lot of eyes sneaks up on Berk while he's trying to unclog a drain. Another thing that sucks things into its mouth climbs out too, and in the end solves both his problems.

All the rubbish Berk keeps throwing down the trap door comes to life and starts spitting slime at him.

Berk tries to pick mushrooms for the Thing Upstairs's breakfast, until one of them runs off.

Fed up with running around after the Thing Upstairs, and fending off the trap door monsters, Berk leaves.