A wicked wizard is stealing animals in the zoo. Of course you won't let this happen just like that: that's why you call in your guinea pigs' help. They make chewing gum bubbles, that cover and defend the animals. Pull the lever at the right moment and sling the guinea pigs to the animals. When all the animals are covered with chewing gum, your mission's accomplished and you can move on to the next level.
Click at the right moment to pull the lever.