The short starts with SpongeBob and Patrick in some kind of time travel machine. SpongeBob states that they can go back to the past to see the young Mermaid Man and Barnacle Boy. Patrick becomes excited by this, so he takes one of SpongeBob's arms and presses the Go button on the time travel machine.
First, they see young Mermaid Man and Barnacle Boy in the pioneer days. SpongeBob does not like this, however, he uses two arms and presses the Go button again.
Next, SpongeBob and Patrick see Mermaid Man and Barnacle Boy riding a dinosaur in prehistoric days. SpongeBob thinks him and Patrick went too far back in the past and uses three arms to press the Go button again.
Thereupon, SpongeBob and Patrick see an advanced computer Mermaid Man and Barnacle Boy. SpongeBob thinks they went too far in the future and Patrick's head accidentally falls on the Go button.
Finally, SpongeBob and Patrick travel back to when Mermaid Man and Barnacle Boy were babies. SpongeBob and Patrick hear crying from a baby crib, so they walk over to the crib to see what is wrong. Baby Mermaid Man and Barnacle Boy stop crying and say, "Change our diapers." SpongeBob and Patrick become scared of this. Suddenly, an announcer is heard and says "Will SpongeBob and Patrick get to see their superheroes in their super prime?"
|( ‣ ) Associated production music|
|( • ) Original music|
|( ◦ ) SpongeBob music|
‣ The Adventurers - Paddy Kingsland [The opening]
‣ The Pirate's Waltz - Robert White [Mermaid Man and Barnacle Boy ride old-style bicycles.]
‣ African Conflict - Norman Dane [Prehistoric Mermaid Man and Barnacle Boy]
‣ ? - Nicolas Carr [Mermaid Man and Barnacle Boy robots]
‣ Toy Piano - Nicolas Carr, Barry Anthony [Mermaid Man and Barnacle Boy as babies]
‣ Shock (f) - Dave Hewson [SpongeBob and Patrick scream.]
‣ Mermaid Man and Barnacle Boy Action Theme - Michael Bolger, Nicolas Carr ["Will they get it right?"]