The eighth episode of the second season of Dennis the Menace (1986), and the seventy-third episode overall.
A Froggy Day
Dennis is searching for his pet frog Willy, who escaped from the house. He and Joey search for him in the swamp, where they encounter a Frenchman named Pierre who's captured a number of frogs, including Willy. He promises the boys he'll take him out for dinner, but after Margaret tells them the man is a chef who cooks frogs as a special dish, the boys go to his restaurant and mount a rescue of Willy and the other frogs.
Loch Ness Mess
The Mitchell family is in Scotland, where Henry is part of an expedition to find the Loch Ness Monster. Dennis accompanies them and is the first to spot the monster, but it quickly disappears back in the water before the rest can see it and call it a day. During the night, Dennis and Ruff explore the castle where they're staying and go below, locating a cavern that goes underground to a small lake where they find the monster and become friends with her. The following day, Henry and the expedition team go out again, only to become endangered when a storm causes their boat to take on water, being on the verge of sinking. Dennis goes to Nessy for help and they team up to make a rescue. With the storm heavy as it is, the team is unable to see how they're being rescued and Nessy is able to get back into the lake unnoticed. The following day, when the Mitchells leave for home, Dennis goes back quickly enough to say goodbye to Nessy, who obliges with a goodbye of her own.
Box Office Smash
Dennis and Joey have a tough time when they plan to go to the movies. First, Dennis has to bring Ruff home since dogs aren't allowed in the theater. Then, an angry usher puts the boys in the back of the line being that he won't allow Joey to save Dennis' spot. The boys manage to reduce the line to get in with a little scheme, then help kids get treats from a candy machine. The usher chases the boys to the point where they get into the projection room and tamper with the machine. The usher eventually throws the boys out, but Dennis was able to get the reel of the film they wanted to see and pulls it out frame by frame to show Joey how the story unfolds, to the boys' delight.
"A Froggy Day" provides examples of:
- Free the Frogs: In this episode, Dennis and Joey meet Chef Pierre, who is catching frogs, one of which is Willy. When Pierre tells Dennis that he is going to take Willy to his place for dinner, Dennis thinks that Pierre is going to give Willy a nice meal to eat. Dennis later finds out from Margaret that Pierre owns a French restaurant where people eat frog legs. Upon hearing this, he and Joey sneak into the restaurant to save Willy and the other frogs.
- O.O.C. Is Serious Business: Alice is surprised when she sees Dennis cleaning his room for once. Dennis explains to her that he isn't; he's looking for Willy.
- Totem Pole Trench: Dennis and Joey do this to sneak into Chef Pierre's restaurant, with Dennis on top and Joey on the bottom. A couple times, Pierre hears Joey talking from inside the coat, and Dennis always covers it up by saying his stomach can talk.
"Loch Ness Mess" provides examples of:
- Bannister Slide: Dennis does this in the Scottish Castle on his way to find Nessie. He slides into a suit of knight's armor as a result.
- Big Storm Episode: This episode's climax has Henry and Professor Smith get caught in a seastorm during another attempt to find Nessie. When Henry's boat is in danger of sinking, Dennis gets Nessie to save it.
- Bookcase Passage: A variant; when Dennis finds a sword mounted on the wall, he takes it, revealing this kind of passage that takes him to where Nessie lives.
- Cassandra Truth: Dennis sees Nessie, and he tries to tell Henry about it, but Henry doesn't believe him.
- No Waterproofing in the Future: Dennis accidentally shorts out Henry's motion dectector when he tosses his can of root beer in the air after seeing Nessie.
- Stock Ness Monster: Dennis meets the legendary Loch Ness Monster, Nessie, and befriends her.
"Box Office Smash" provides examples of:
- Dog Walks You: Invoked: Early in this episode, Dennis ties Ruff to his doghouse to keep him from going to the movie theater with him. However, Ruff manages to pull the doghouse out by its roots and run all the way to the theater, dragging it along. To get Ruff back to his house, Dennis places Ruff's doghouse on his and Joey's skateboards and rides atop it. However, this plan is compromised when Ruff chases a cat.
- Get Out!: The usher says "Out! Out! Out!" after Dennis and Joey cause him to get tangled up in film reels.
- Jerkass: The usher. He refuses to believe Joey when he says he was holding Dennis' spot in line, and forces them to the back when Joey mentions Ruff. He also takes delight in children losing their money to his candy machine, saying their loss is his gain.
- Movie-Theater Episode: Dennis and Joey go to the movie theater to see Jojo the Wonder Dog in this episode, where they try to evade an angry usher.
- Painted Tunnel, Real Train: Dennis and Joey evade the usher during a screening of a cowboy movie. They run through a pair of saloon doors in the film itself, but when the usher chases after them, he rips right through the movie screen.
- Percussive Maintenance: When a boy loses his money in a candy machine without getting his treat, Dennis knocks on the machine, getting the candy out. This angers the usher, but delights the other children.
