The episode begins one night in the attic. The Mayor sneaks in and steals an opal on a mummy's tomb. He plans to sell the opal and get rich off it.
The next morning, The Action League, The Chief, and Bill the Lab Guy find the opal has gone missing. The Chief asks Bill to give him an analysis. Bill tells The Chief that the opal got ripped off. He is then grateful that nobody opened the sarcophagus, otherwise, the Mummy would escape. Sure enough, The Flesh opens the sarcophagus, releasing the Mummy inside. Bill then tells the League to run while they still can, now that The Flesh has awakened the Mummy. Stinky tells them that he's not afraid of the Mummy's curse, but decides to leave for a dentist's appointment. The Rest of the League join him. The Chief calls them a bunch of fraidy-cats and follows them. Sure enough, the Mummy awakens.
On the couch, The Flesh, Thundergirl, Stinky, and Meltman begin to look for the Mummy's opal. The Flesh tells the rest of the League he found something. Stinky asks if he found the opal, but The Flesh reveals that he found the TV remote control. The League decide to abort their mission and watch television instead. However, they all want to watch something different. Stinky wants to watch Oprah, Meltman wants to watch Scooby-Doo reruns, and Thundergirl wants to watch Felicia.
Back at Action Headquarters, The Chief tells Bill they'll be in a lot of trouble if they don't recover the missing opal. Bill tells him that he's more worried about the Mummy's curse. The Chief tells him that he doesn't believe in curses, just as the Mummy sneaks up behind him. A scared Bill tells him he's late for a dentist's appointment, and The Chief turns around and sees the Mummy. He screams in fear as the Mummy zaps him with his laser eyes, smashing him to pieces. The Mummy then continues his search for the opal.
Meanwhile, The Action League is still on the couch, trying to decide on what to watch on TV. On the Mom's Vanity Shopping Network, the Mayor is advertising the Opal on TV. They find out The Mayor has the opal and the Mummy is looking for it. Stinky picks up his spear gun and shoots at the Mummy, which has no effect as the Mummy pulls the spear out and tosses it back at him. Thundergirl flies towards the Mummy, but gets punched back and lands on the rest of the League. The Flesh then lunges at The Mummy, but The Mummy grabs him and tosses him into a vase. He then is about to attack Thundergirl, Stinky, and Meltman. The Narrator asks the viewers if the Mummy will defeat the league and if The Mayor will make a handsome profit from the stolen opal, then tells them to stay tuned for Part 2.
In the second act, just as the Mummy is about to attack Thundergirl, Stinky, and Meltman, he hears The Mayor advertise the opal on television. He then decides to go after the Mayor, and Stinky, Meltman, and Thundergirl decide to follow him. An angry Flesh then decides to break his way out of the vase by pushing it off the table.
At The Mayor's studio, The Mayor continues advertising the opal just as The Mummy appears. Thundergirl, Stinky, and Meltman arrive aboard the Action Mobile and find the opal on the dresser. Bill appears in a tractor, with the Mummy's sarcophagus in the trailer and tells them that in order to defeat The Mummy, they must lure him inside the sarcophagus and recite the incantation. The Mummy zaps The Mayor with his laser eyes, and the opal rolls towards Meltman. He tosses it to Thundergirl, who then tosses it inside the sarcophagus. The Mummy goes inside the sarcophagus as Bill closes it, reciting "Ohwha, Tajer, Kiam", then telling the League that now the Mummy can sleep for another 3,000 years. Thundergirl, Stinky, and Meltman cheer as The Chief arrives, wrapped in bandages. Bill turns around just as The Flesh arrives with a mallet. As The Chief tells Bill that he owes him an apology, for he was right about the curse, Bill tries to warn The Chief that The Flesh is about to attack him, but The Chief interrupts him. The Chief turns around as The Flesh, mistaking him for the Mummy, attacks him with the mallet. Thundergirl, Stinky, Meltman, and Bill all laugh as the episode ends.
- Thundrgirl (singing): "Thundergirl, fighting the Mummy," (The Mummy throws her at The Flesh, Stinky and Meltman) "Then again, maybe not."
- Narrator: "Will a miffed Mummy make mincemeat out of our zeroes, I mean, heroes? Will The Mayor make a million on a museum marvel?"
- The Mayor: "Quantities are limited, order now!"
- Narrator: "Find out in the action-swiped conclusion of Action League Now!"
- Narrator: "A jewel taken, a mummy awakened. As a familiar foe auctions off an opal, an enraged relic takes on... the Wuss Squad!"