Safety Second

Plot
The cartoon short begins with Jerry and Nibbles asleep in their beds. Jerry looks at his calendar and seeing it's the Fourth of July, he wakes up Nibbles. He instantly brings out firecrackers, but Jerry puts them back into the shed. The mouse gives his calendar a look again and sees his daily quotation: "Make it safe and sane", meaning that fireworks aren't allowed this year. Jerry and Nibbles then go outside and enjoy their holiday with noisemakers with Jerry showing him it's still the Fourth of July without fireworks, before Nibbles (not one to follow the quotation from earlier) lights a firework from his nappy. Jerry grabs it away and then fails to throw it off before the firecracker explodes on him. Jerry then holds out his hand as if to say, "Give me the rest of them." Nibbles hands him another tiny firework from his nappy and smiles before dashing away. Seeing through this, Jerry then picks up Nibbles and turns him upside down, and he finds that Nibbles had a sizable amount of fireworks hidden in his nappy. As if he punished Nibbles, Jerry gets him to stand in one of the corner, but no sooner does Nibbles repeat his transgression with a firework under the bed before leaving, and Jerry is again blown up by the dynamite before he can toss it out of his front door. Nibbles then hides under his sheets.

Jerry then goes outside to relax in a hammock while Tom lights a firework underneath Jerry. The firework explodes and wakes up the mouse who, believing that the explosion was Nibbles' doing, walks around the tree to see if the little mouse was there but runs into Tom instead, who slaps Jerry with his own eyelid and traps him. When Tom lets go, Jerry is kneeling over a clenched fist. The mouse points at it, and Tom inspects it, and Jerry responds by using his other fist to punch the cat in the eye. Jerry jumps into a hole in the ground and Tom uses a pickaxe to try and dig the mouse out. Nibbles, who observes this event, loads a rocket into the drainpipe, which picks up the cat and sends him on a ride across the yard and into the clothesline.

Jerry hides from the raging cat in a barrel and Tom uses a garbage can lid to trap him. Nibbles, again watching from a distance, paints another firework with glue and "graciously" hands it to the cat. Tom lights the firework and tries to throw it into the barrel, but spots the situation before he runs too far away and continues to attempt to throw it, but fails as it is stuck to his hand. Tom now tries to soften the explosion by sitting on the firework, but made a bad choice as to where: under the flowerbox. The explosion propels Tom headfirst into the flowerbox, smashing through it, and pots fall on his head.

Now ready for revenge, Tom chases Nibbles who runs into the back end of a firework. Nibbles lights the firework, empties the gunpowder, and chases the cat. He corners Tom, but after the fuse runs out the ruse is exposed. Nibbles pops out and is caught. However, he throws a tiny firework at Tom and leaves as Tom takes it, believing it to be harmless, laughs at it, and balances it on his nose. At that point, the tiny firework explodes powerfully in his face.

Tom then loads a bunch of fireworks outside Jerry's front door and lays out the gunpowder, but Jerry breaks the connection to his door and lights the gunpowder. After he is finished laying out the gunpowder, Tom prepares to light it, but Jerry's flame does the work for him. Tom sees a big explosion of the gunpowder can is imminent, but cannot escape it in time. Tom chases both mice, and they use a firework to shoot colorful fireballs at Tom. Tom runs away through a barrel and the basement window and sneaks behind Jerry and Nibbles, who have lit another rocket firework and have loaded it into the barrel where Tom was. Tom grabs the firework from them, only to get launched into the air by it, ending up in result of a firework display of death.

Jerry then wipes his hands together and heads over to Nibbles and his noisemakers while Nibbles lights one more firework. With nowhere else to hide it, he stashes it in Jerry's noisemaker. Jerry pats Nibbles on the head and goes to blow in his noisemaker. Knowing the consequences, Nibbles attempts to stop Jerry from doing so, but the mouse only pats him on the head again, then blows into it and it explodes, giving him a Blackface/sunflower appearance. Jerry looks at Nibbles, annoyed, as Nibbles smiles innocently and plays with his noisemakers.