It's Ronald's birthday and Hamburglar, upset that he didn't get Ronald a present, invites everyone to a fake amusement park known as "Birthday World" to celebrate, run by an evil mad scientist named Professor Thaddeus J. Pinchworm. Everyone is amused at first, but they can no longer escape and no longer fall for the poor designs of the rides until they ride a rollercoaster which turns them into babies (both Franklin and Tika are wearing diapers) and they need to find out how to return to their original ages, even though their certain abilities are limited since they are toddlers.

Ronald and his friends going on a camping trip in the Far-Flung Forest where Ronald discovers an old house which he assumes is haunted by a ghost called the Far-Flung Phantom. The campers are forced to stay in the old house due to the stormy weather where a holographic head named Franklin leads them through a challenging game which will eventually help them to escape.

The gang travels to Scotland where a scientist attempts to build a replica of the Loch Ness Monster. Birdie befriends the Loch Ness Monster who wants his existence to be kept a secret.