Stanley and Mary-Jane view their new home and soon find a sink in their basement which leads to civilization, called Drainland. They soon discover mutant monsters, some of which are friendly.

Stanley starts his first day at school along as Mary-Jane is pretending sick at home, she soon decides to travel down the portal to Drainland again, however she soon finds herself being chased for stealing a Cleansing Sea plant, meanwhile Stanley travels down again to rescue his sister from a large amount of acid which was tipped down the sink.