Stella has always been different - she's a superhero! But this makes her rather sleepy at school and when she's caught sleeping in the class, Stella has to stay behind. She has to write and essay on a time capsule that has been buried at the school by an old student. On the radio, she hears that a robber Bob Biggins has escaped but she can't slip away to change into her supersuit. To her surprise though, the robber bursts into the classroom! It turns out that he hid his fortune in a priceless stamp in the time capsule but she can't use her powers without her suit on... But with her whizzy wheelchair, Stella is able to catch the robber anyway and saves the day!