 The series follows the adventures and endeavors of the title character and his various friends in the underwater city of Bikini Bottom . In this episode , SpongeBob feels neglected and ends up a nuisance when he tries to hang out with the other characters . They all call him " Idiot Boy " , so SpongeBob decides to pack up and leave Bikini Bottom . Along the way , he accidentally bumps his head , making him lose his memory . SpongeBob wanders away into a new place called New Kelp City and attempts to get a new job , unaware he is becoming a target for a criminal gang known as The Bubble Poppin ' Boys , while Patrick , Sandy and a reluctant Squidward try to find him . 
