Plot summary
Doodle finds that a mysterious intruder is stealing the Keystones that allow travel in the gates between the lands. She wakes Noodle and together they set off to find the intruder, traveling to the top of Haven Tor along the way. In each of the worlds they see big black feathers and a large flying figure along the way. At the end of each world, the ruler of that realm thanks Noodle and Doodle and gives them a treasure. At the end of the final realm, they see that the magpie was looking for something shiny in order to reopen a portal to take them home.
In approaching the bird, the 4 gifts given to Noodle and Doodle from the ruler of each realm work as keys and reveal "the Great Shiny." It then activates the portal, which allows the bird to go home. However, it soon returns, asking for the duo's help.
Credits
Adapted from Wikipedia contributors, Snake Pass (video game). Section headings and formatting adjusted.