The four Bankie children are named Ahmad, Ibrahim, Aaliyah and Ja'far. Always on the lookout for an adventure, their unique qualities help guide the way and save them from trouble.

Ibrahim frequently leaves his leftover lunch from school in his school bag. When the children are tidying their rooms, Ibrahim discovers an old, rotten apple core in his school bag. Ahmad is curious to see more and tests out his new microscope. They discover much more than mould on a rotten apple.

Join the Bankies on their latest adventure. What mysterious discovery do they find on the mould on Ibrahim's apple? How do they escape from trouble this time?