Darkwing and Launchpad interrupt two goons in tracksuits robbing a museum, preventing them from stealing all of their treasures. They identify a logo on their gear as from the professional gym of Jock Newbody, and Darkwing decides to infiltrate the place as his civilian identity Drake...only to learn that Mr. and Mrs. Muddlefoot have a coupon for the place and plan to join him. Things quickly go downhill, not only because the 122-year-old Newbody needs the feather of a hero to complete his vitality potion, but also because Darkwing's fitness bracelet ends up fused with Herb's...
This episode contains examples of the following tropes:
- Be Careful What You Wish For: Newbody wanted to create a Fountain of Youth elixir to extend his life. Unfortunately, he got it in a major way when an overexposure caused him to regress to an infant, alongside Slim and Flex.Darkwing: Youth really is wasted on the young.
- Chained Heat: Darkwing and Herb Muddlefoot spend a good part of the episode stuck at the wrist, after Herb encounters a rowdy guard dog and Darkwing tries to save him, only to end up slamming them both into an electric fence that fuses their work-out bracelets together. After an exposure to Newbody's elixir temporarily regresses them to infants, their wrists become thin enough to slip out.
- The Dog Bites Back: Flex and Slim get shut in a locker by Newbody after he's revitalized, stating that he doesn't want to share his secret to immortality. However, they know the combination and escape after Newbody's regressed to a child, apprehending him and planning to take the formula for themselves...right before Darkwing and Herb blow it up with their own time bomb, regressing them to infants as well at the same time.
- Face Your Fears: Darkwing and Herb, after losing a fight with Jock Newbody, end up wrapped up to some gym equipment next to a time bomb. Darkwing can only get free if Herb does the one thing he hates more...completing a sit-up, as it will let Darkwing's trapped arm get into the right position. Herb is absolutely hesitant, until Darkwing tells him to do it for his wife, at which point he tries his best and succeeds.
- Fat and Skinny: The goons Slim and Flex, respectively.
- Fountain of Youth: Jock Newbody's plan is to have his goons steal the ingredients for an elixir that could revitalize him back into the body of a young hero. He eventually succeeds, after using one of Darkwing's feathers as the final ingredient. However, a later fight with Darkwing and Herb ends up giving them all another dose, regressing them to infants; Darwing and Herb end up using an antidote Newbody prepared earlier in case the potion failed, while Newbody himself (as well as his two goons) are stuck in the bodies of babies at the episode's end.
- Hoist by His Own Petard: In the end, Herb used Newbody's own bomb to destroy his youth elixir.
- Immortality Seeker: Jock Newbody, to the point that he used every health and medical method possible to extend his life (to good effect since he managed to keep himself going for 122 years) before finally creating a youth elixir for himself.
- Imperfect Ritual: When Flex and Slim mistakenly believed Herb was Darkwing, they ambushed him and took one of his feathers. When Newbody added it to his youth elixir and drunk it, he ended up looking like Herb (right down to his Hawaiian shirt).Newbody: Aah, I feel like...(Bewildered) I feel like bowling.
- Mistaken Identity: When Herb decides he's had enough of the gym's strict scheduling and hardcore exercise, he tries to flee, only for Newbody's goons to think he's Darkwing in disguise and take one of his feathers.
- Punny Title: Based on the phrase "You bet your life."
- Sincerity Mode: While he has trouble getting it out, Darkwing thanks Herb for saving his life. Herb is naturally left in awe.
- Watch Out for That Tree!: In trying to save Herb from a guard dog, Darkwing acidentally slams them both into an electric fence. The resulting electric shock melts and fuses their workout bracelets together, resulting in them being stuck at the wrist.
- You Fool!: Newbody, to Slim and Flex when they brought him the wrong feather, causing his elixir to make him look like Herb.
