Storyline
Specter kidnaps the Professor, Aki, Sayaka, Satoru, Hikaru and shrinks his laboratory, with Kakeru and Natsumi and who he kidnapped inside. Despite that, the lab is at least small enough to be disguised as a Pipo Helmet, which then Natsumi and Kakeru have to control the monkeys (named Piposaru in Japan) to help rescue their friends as well as defeat Specter.
Read more about this topic: Saru! Get You! Saru Saru Big Mission