The king is sleeping peacefully in his bed, then Jerry and Tuffy climb a nearby table. However, Tuffy loses his balance and grabs Jerry's outfit, but cannot keep from falling. Jerry looks at where Tuffy fell, but then Tuffy pops up behind Jerry and scares him. Jerry is miffed, but Tuffy explains in French what happened. Jerry shushes him and motions for the little mouse to follow. Jerry jumps into a wedge of cheese and looks through the holes. He keeps stealthy as he spears a bit of cheese on his sword. Then, he sees Tuffy has speared a grape, which bounces into the king's mouth. The king's mouth starts to inflate as he suffocates, but Jerry causes the grape to be swallowed safely down his throat. Jerry runs away and motions again for Tuffy to follow, but Tuffy runs into a teacup and breaks it, waking up the king with a start. The king glares at Tuffy, and then Jerry stabs him in the nose. He cries out and calls for "a cat". Tom answers the call moments later, and is chastised by the king in French about his doing whatever he wants when he needs help ("Goofing off?"). The king then warns Tom not to let the mice disturb his nap again or else he will have the cat beheaded. He then goes to sleep and Tom marches around the king's bed; then he sticks his tongue out at him and is bopped on the head. Tom resumes marching until he hears Jerry eating cheese. Tom gets ready to skewer the mouse, and then Jerry points to Tuffy dropping a vase. Tom catches it on his sword-blade.
Jerry and Tuffy then throw the entire platter of dishes down and Tom is forced to catch all of them on his sword, head, arm, and foot. Tom uses his remaining foot to tiptoe out of the castle so that the dishes falling do not wake the king and then rushes back in. He steps on tacks scattered by the two mice and goes out again before yelling out in pain and pulling out the tack. Tom runs back in for the second time and barely stops before he steps on the tacks again. Tom puts a gauntlet on his feet in order to tiptoe across the tacks without being hurt. Tom then confronts Jerry, but Jerry stabs him in the nose. The cat is forced to cover the king's ears so that he does not hear his cry of pain. Tom spots some champagne corks and then hears mysterious clanking. A suit of armor is being used as a puppet, and it dances noisily. Jerry raises the visor and sees only Tom, standing nonchalantly next to the suit. He gestures toward the king, whose ears are plugged with the corks, and then slices apart the suit of armor. Jerry dodges while Tuffy escapes and plugs the king's nose with clothespins, which causes his face to bloat again. Tom has caught Jerry on the end of his blade, but Jerry points at the king, and Tom can only watch as the clothespins and corks are blown off and the king wakes up. Tom plays a soothing violin tune to cause the king to fall asleep again.
Tom chases the mice outside, then locks all the doors and swallows the key so that they cannot get back in. However, they bring a crossbow and shoot an arrow through the keyhole into Tom's backside. Tom tries to hold his scream of pain in until he can get outside, but with no way to get outside, Tom can't help but let his scream out inside the room. The king wakes up and yells at Tom in French that he will prepare to behead Tom. However, the mice realize their mistake in letting Tom get beheaded, so Tuffy saves Tom's life by singing Frère Jacques (Are you sleeping?) to the king, sending him back to sleep again. Tom and the mice tip-toe outside the room, shaking hands together, and having a fight. Tuffy says: "C'est la Guerre." ("That's war.") during the break and resume his fight.
- Following on from The Two Mouseketeers, Touche, Pussy Cat!, and Tom and Chérie. this is the final cartoon based on The Three Musketeers.
- This is the first time when both Jerry and Nibbles felt sorry for Tom for almost getting executed, which led Nibbles to be the only one to sing to the king back to sleep like an angel (which he's the only mouse who can communicate to humans). Possibly it took place after "The Two Mouseketeers" they witnessed Tom getting executed (and later got resurrected with surgery), and cannot let that happen again because all they wanted was to have fun with Tom, not see him get eternal punishment.
- In the scene when Tom gets ready to skewer Jerry and when he points to Tuffy dropping a vase, instead of Tuffy, Jerry is shown dropping the vase. This could possibly be due to Tuffy miscolored brown instead of grey.
- In one scene, Tom cannot get out because he has swallowed the key, but then the next scene shows him opening the door and walking through it. However, he could have gotten the key out, or Jerry brought another copy of the key.