After he sees the Fat Controller's grandchildren with chickenpox, Henry worries about catching the disease himself. This feeling grows stronger after he sees Thomas, Paxton and Gordon with spots that he thinks are due to chickenpox.

Thomas is sent to take a special crate to the Town Square from the docks, but Cranky accidentally drops the crate and he hides it away from Thomas, so he cannot find it. Salty eventually finds it, but Thomas drops it again, before it is revealed what is really inside the crate.