Uru: The Path Of The Shell is the third and final chapter of the Uru saga. It continues the story of the restoration of the D’ni civilization, but shifts the focus from the failed efforts of the D’ni Restoration Council (DRC) to the prophecies of the Watcher, about a person known as the Grower who has the power to bring new life to D’ni, and the quest of Guild Master Kadish (whose Age of Kadish Tolesa, known for its complex puzzles, was explored in the base game) to fulfil that prophecy.
The expansion pack begins at the Great Tree Pub, also known as the Watcher’s Sanctuary. This is the location of another one of Kadish’s puzzles, the eponymous “Path Of The Shell.” The Path limits access to the Great Tree to those who could properly interpret the Watcher's prophesies. So far only Kadish has ever been able to solve the maze, as it was a deceit intended to convince others that Kadish himself was the Grower, or savior, foretold in the prophecy.
Two major Ages are introduced and explored in Path Of The Shell. The first Age is Ahnonay, which was Written by Kadish to demonstrate his abilities to travel through time, another sign of the prophesized Grower. Ahnonay is meant to depict the same Age in three stages, past, present, and future. However, by exploring the Age further it is revealed to be an illusion, as the three “time periods” actually are all contained within a single Age.
The second Age is Er’cana, an industrial Age which contains equipment that produces pellets rich in nutrients which were intended to feed the luminescent algae in the D’ni cavern lake. Kadish, who designed and oversaw the construction of the equipment, intended to use the pellets to further solidify his claims to be the prophesied Grower who would bring light to the caverns.
By exploring both these Ages, the player gains clues that will help solve the Path Of The Shell. Once the puzzle has been solved, the player is linked to the Myst Library, where they must solve one more puzzle to gain access to the linking book to K’veer. Once in K’veer, Yeesha reveals that she, not Kadish, is the Grower. Yeesha also reveals that “His body no longer lies in his vault,” implying that she traveled through time and saved Kadish, who was presumed to have locked himself in his vault at Kadish Tolesa and died among his riches.
The game ends here, but after the ending cutscene the player can make their way to the vault at Kadish Tolesa. At first it looks like Kadish is dead, as his skeleton is found in the vault, however exploring a bit more the player will find a linking book to an alternate version of the vault, where they player will find that most of the treasures in the Vault has been removed, along with Kadish's body. Note fragments scattered around the vault reveal that Yeesha has the “powers of gods” and saved Kadish’s life.