A mysterious crop circle has appeared in farmer Gus' sweet potato field. Seeing Zorori and the twins investigating, he assumes they're the one who did it. Zorori tells him it wasn't them but a UFO that did it. Gus doesn't believe them and tells them to catch the UFO that damaged his crops. He then traps them in the enclosure with an electric fence. Zorori wonders what to do while Ishishi and Noshishi decide to eat some of the sweet potatoes. Suddenly, an actual UFO appears and abducts Noshishi! Zorori and Ishishi are stunned that a real UFO showed up and can do nothing as Noshishi is taken to space. Now Zorori and Ishishi must build a rocket to go and rescue Noshishi, but how will they do it? Based on book 11.