Tom chases Jerry inside a nightmarish mansion in the forest called Doom Manor.
Jerry walks in a forest enjoying the scenery and flowers, unaware that Tom was waiting to capture him with a snare. Jerry walks by and sees the snare. He sneaks away and Tom comes to the snare to see what went wrong. (even leaving his Leg to the snare's rope) Jerry then pulls the rope's knot, snaring Tom. The chase starts as Tom chases Jerry deeper into the forest. Jerry then goes into a hollow log, and Tom jumps upward to cut Jerry off successfully. Jerry goes back, as Tom crawls then chases Jerry. Jerry then wedges the log with a rock, and with a sharp blow, Tom crashes into it.
The chase then leads both of them to a haunted mansion, as Jerry desperately knocks on the front door. The door opens, and a Frankenstein-esque butler named Ego appears to the terrified Tom and Jerry, telling them that they're both trespassing in Doom Manor. Ego presses a button, which opens a trap door, throwing Tom and Jerry into the dungeon. A few seconds later, a haggard green-skinned woman introduces herself as the sorceress named Groteska, showing interest in Tom, as the witch's pet; but with Jerry being used for experiments, so she uses magic to generate a wood cage, trapping Jerry inside. Then Groteska shows Tom a gallery of her deceased pet cats, which makes him nervous. At the laboratory, Groteska places Jerry's cage as she plans to experiment Jerry after her beauty sleep and entrusts Tom to stay.
Jerry then opens his cage as he tries to escape, but Tom grabs a spoon and flings him inside a glass beaker of green liquid. Tom then grabs Jerry before he mutates into a monstrous mouse, more than twice Tom's size. Tom who becomes scared of Jerry's monstrous form, hides in the barrel, but then Jerry smashes it into pieces. Jerry then grabs Tom by his tail and thrashes him, but then shrinks down to his normal state and full-size height. The tables turn as Jerry runs back to the green liquid successfully, after tricking Tom to pull on a chain, causing a cage to flatten him. Jerry sips the liquid, but Tom traps him in the beaker. However, it could not stop Jerry's transformation to his monstrous form. Jerry then flings Tom into the lab equipment and into the cauldron. When Monster Jerry is about to continue clobbering Tom, he shrinks down to his normal size again, Jerry sips more of the liquid, but Tom grabs it away and swallows the liquid whole to retaliate Jerry, but Tom becomes a frog, then an elephant, and then in his monstrous form, but then shrinks down to Jerry's height. After Groteska returns to see that her laboratory has been trashed, she then tells Ego to go after Tom and Jerry who escape from Doom Manor, after Tom enlarges back to his full size. Tom and Jerry stop to catch their own breaths as Ego captures them. However, Ego says he wanted to get out of the nightmarish mansion for years, looking for a career in Horror Show Biz, and after Ego asks to come along, Jerry silently accepts. Ego then tells the pair that he can do other talents as the three walk off into the forest, as the sun goes down, then we fade to black.
- As Jerry sneaks to see Tom behind a tree, Tom's eyes are white instead of yellow.
For the gallery of Doom Manor, click here.