1x31 - The Bullwinkle Show

A last-second reconsideration of orders from headquarters (the message didn't say KILL MOOSE; it actually read DON'T KILL MOOSE) means Boris has to save Rocky and Bullwinkle, whose brilliant idea to retrieve the last mooseberry bush on Mooseberry Island (SWIM THE RIVER!) has one tiny flaw (Bullwinkle doesn't know how to swim!).