Author: Alan MacDonald; Welsh Adaptation: Mari George.

Series: Cyfres Academi Archarwyr.

When Dr Sinister hatches his latest plan to take over the world, and creates evil custard that turns children into deadly blob monsters, what better place to try it out than an unsuspecting school? Little does Dr Sinister realise that Mighty High is a school for superheroes - they are all acting ordinary to pass the school inspection!

Awdur: Alan MacDonald; Addasiad Cymraeg: Mari George.

Cyfres: Cyfres Academi Archarwyr.

Croeso i Ysgol y Nerthol, sy'n meithrin archarwyr y dyfodol. Mae arolygwyr yn yr ysgol ac mae'n rhaid i Siôn a'i ffrindiau'n guddio'u pwerau arbennig rhag i Ysgol y Nerthol orfod cau! Yng nghanol hyn, mae gan Doctor Drwg gynllun dieflig i orfodi'r plant i fwyta Cwstard Cas er mwyn eu troi'n Flobiau Erchyll peryglus.