From the manual:
RAT* ALLEY is infamous among the legions of the plumber. Rumor has it that
extremely large rodents live in the maze of tunnels that make up the area. The last
plumber that ventured into RAT ALLEY disappeared without a trace. (The only
clues they found as to his demise were a hard hat bent to look like Mickey Mouse
ears, and a pipe wrench with a bite out of it.)
You are Larry Bain, ace Plumber, of Rodent Rooter plumbing service. Your job is
to install pipe through the many levels of RAT ALLEY.
MOUSKATTACK is an unbeatable blend of quick thinking arcade action for one
or two players.