PART 1
Dipper arrives at the Mystery Shack to find that Stan has built several additions to the building. Dipper enters to find that the inside still looks the same, even though it feels smaller. He hears a noise and goes outside to investigate, only to be attacked from above by Mabel. Soos comes outside, at first thinking the twins are all part of a dream he is having, but he eventually comes around.
Soos tells the twins that the attic is still ready for them to sleep in and reveals that he is staying in the building until everything gets sorted out. Mabel mentions her theory that Stan isn't dead and it is all a prank, but Dipper snaps at her that they need to face the reality that Stan died, and the three go to bed without saying much else to one another.
Dipper wakes up the next day and also wakes up Mabel, who takes longer than he believes she should have to get ready, putting him in a bad mood. The twins brag about their vehicles and leave into town to receive their copies of the will. The two will own the Shack when they turn seventeen, among other details that are lost as Mabel ignored most of them, still believing Stan to be alive.
The two go to the funeral home, and Mabel's insistence that Stan is still alive finally causes Dipper to snap and say he just wants everything to be over. The caretaker, a tall man, checks the coffin to make sure Stan's body is still there. Mabel takes Dipper's words as he wants to leave and say goodbye to her, and they start yelling at each other until Soos, along with Wendy, show up.
The caretaker begins the ceremony, with Dipper saying a few words before Mabel takes the stage. Still believing Stan is alive, she opens his casket. After a few second of him not responding, she runs out, finally coming to terms his death. Dipper follows her and reveals that he felt the same way, that Stan wasn't really dead, but he tried to deny it in an effort to get over everything quicker. The twins admit they missed each other before Wendy and Soos find them, and the four head back inside, Soos saying he thinks the caretaker could be a vampire.
When they return, they discover that Stan's body has disappeared. Soos, thinking the caretaker did something, guards the tall man as the rest of the group searches the funeral home and the woods around it. They meet up again without finding anything and hear a noise outside, but when they get out, there is nothing to be seen. They go back inside and examine the casket, discovering a glowing blue cylinder and a piece of string.
The group returns to the Mystery Shack and begins to try to figure out everything, Soos getting the Journal out of storage to help with the investigation. They theorize that the blue cylinder is a battery of some sort, and while suspects are unclear at the moment, they discover the string smells familiar and tastes sweet. They realize the string is actually candy, and the twins decide to go to the candy shop in town to continue the investigation.
PART 2
While Mabel gets high on candy, Dipper interrogates the shopkeeper of the candy store and discovers the candy floss is supposed to function more like an air freshener than a treat. He sniffs it again, but is still unable to place the scent. Mabel takes the floss and leads them to the library, following the scent of newly opened books.
The twins go into the library and, after discovering a draft, find a secret passage, the scent being masked by more candy floss. Entering the passage, the bookcase closes, and they are faced with a crossroad. Choosing to go right, they follow the path to a large chamber that goes deep into the ground, with a living Grunkle Stan trapped in a cage at the bottom. The twins run down into the cavern and hug Grunkle Stan, who tells them to leave before his captor shows up.
His captor is revealed to be Montana Jeffreys, a treasure hunter who has begun to be ignored by society. He puts the twins in the cage with Stan and has one of his two dogs bring out Dipper's backpack that they stole from his car while the twins were at the funeral home. Montana tries to get the twins to sign over the Mystery Shack, with the intent that the paranormal creatures/objects in and around town will help him restart his career. The twins refuse to sign over the Shack and Montana leaves, his dogs staying behind to guard Stan and the twins.
Mabel starts to try to pick the lock with the leftover candy floss, but the dogs tell her to stop. The dogs, Nadia and Diana, agree to let Stan and the twins go, hoping it will help Montana stop working for money. Dipper grabs his bag and the three of them start to run out of the chamber, Montana and the dogs chasing after them. They grab pickaxes and shovels and start hitting support beams, causing a cave in just as they escape the tunnel. Diana gets her leg trapped under a boulder, but Montana, Stan and the twins are able to get it off of her. Montana retires, and Dipper shows him the blue battery. Montana gives Dipper a second one, saying that while he found it several months ago, he has no idea what it is.
The twins and Stan return to the Mystery Shack, Stan reuniting with Soos and Wendy. Stan asks the twins if they would like to spend the summer with him, but Dipper says no, even though he wants to. The twins pack up and start to head out, leaving behind a depressed Wendy and Soos, but Stan has a feeling that he won't miss them yet.
On the highway, Dipper's heart and mind are clashing. He keeps trying to tell himself that going home is the right thing to do, but his heart want to turn around and go back to the Shack. Mabel passes him, and he finally snaps, slamming the brakes, causing his backpack with the blue batteries to fly open. The twins turn around and go back to the Shack, Stan waiting on the porch for them. Stan reveals his new business plan- The Mystery Manor.
A figure eventually identified as Uki-Dohth is shown observing the town on various monitors, his unknown boss telling him to continue the mission as planned, despite the risks.
Cryptograms:
UDLGHUV RI WKH VWDQV ORVW XQGHUSDQWV. RAIDERS OF THE STANS LOST UNDERPANTS.
20-8-5 19-11-25'19 5-25-5-19 20-21-18-14 20-15-23-1-18-4-19 16-9-14-5-19. The sky's eyes turn towards Pines.
