Yoku's Island Express tells the story of a tiny postman who finds himself drawn into a dangerous adventure against his will. Yoku is a small red ant who goes everywhere with his white ball. The hero arrived on Mokumana Island hoping to relax and bask in the sun. However, everything changed when he learned of a dormant monster that threatens the safety of the islanders. The postman also discovered that the local post office is not functioning, which means he will have to set up a workplace with his own hands.

The gamer will have to control Yoku and move and fight with the help of his ball. The island is dangerous and full of unknowns. The player will have to fight with monsters that serve the sleeping monster. Also available for battle are battles with bosses that are significantly larger than the ant. To hit enemies, you need to direct the ball in the right direction, it will ricochet and cause damage to everyone it hits.

Mokumana is open to exploration. Here the protagonist can deliver letters, make new friends, and also fight with ill-wishers. An important component of the gameplay is the restoration of the post office, so that the protagonist can work better. The plot of the game develops as the territories are explored. Information about enemies can be obtained from local residents. In addition to the story missions, the player has side missions in which the hero needs to help the locals. However, do not forget about the main task – to find and neutralize the supreme monster.