Mister Trouble never hangs around
When he hears this Mighty sound.

"Here I come to save the day"

That means that Rittenhaus is on his way.
Yes sir, when there is a wrong to right
Rittenhaus will join the fight.
On the sea or on the land,
He gets the situation well in hand.

source: http://www.lyricsondemand.com/tvthemes/mightymouselyrics.html