Joey travels to purgatory to rescue “deceased” YouTubers of previous seasons from The Collector of the Dead, who has locked them in her museum. His mission takes a dark turn when he discovers there’s no way home. The group learns they must recover nine Jeweled Keys to open the Collector’s mysterious vault if they have any hope of survival

A pharaoh is wrongfully murdered and awakened from the dead by the YouTubers. They must find his killer and venture into the Sands of Egypt if they want to recover the first Jeweled Key.

The YouTubers enter the Indian exhibit and face off against the bird man of legend, Garuda. He traded his soul for gold and soon the YouTubers will do the same. They are forced to make a deal with a demon goddess if they want to claim the next key.

The Emperor of China needs an heir and a wife or the rebels will invade. The ladies are recruited to play dating games in hopes of becoming his “wife” and the men must escape the bonds of the dragon rebellion and uncover an ancient spear if they want to live.

Camelot has fallen to The Black Knight and the YouTubers must reclaim Excalibur if they want the next key. They recruit Merlin to uncover the secrets of Standing Stone and crown one of them King of Britannia.

The Gorgon returns to the museum from her exhibition and turns Mortimer into stone. The group place Merlin's crystal into a box, summoning Matt and Nikita into Purgatory. Alex tries to shine a mirror in The Gorgon's face so she turns herself to stone, but the group finds out she is immune to this. The YouTubers split up into two groups. One group is responsible for completing the statues to gain a piece of a medallion. The others enter the Minotaur’s maze to get the next piece of medallion needed to claim the next key. However, before they can get the key they must turn The Gorgon to stone. They must do a challenge to assemble a puzzle Colleen and Matt were winning but Nikita knocked over Colleens puzzle leaving Matt and Colleen to lose.

A genie has been trapped in a lamp and the YouTubers must find a way to free him to get the next key. They will have to outfox Scheherazade and her many thieves if they want to find their way out of the Arabian exhibit.

X marks the spot. The YouTubers uncover a treasure map with the location of the next key, but dangerous pirates are hot on their trail. They have to brave Pirates' Bay to find the missing pieces, but only the most pirate-worthy among them will avoid death in this exhibit.

The YouTubers befriend a caveman who leads them into the prehistoric exhibit where they encounter the Cursed God once again. The YouTubers must open his monument while avoiding death by dinosaur.

The Collector returns to the museum with her most terrifying collection yet and unleashes it on the YouTubers. They must journey back through all the exhibits to find the artifacts needed to defeat her and in turn discover the source of all evil.