Wham Episode / The Return to Gravity Falls

• Season One Prologue: The twins get the call that Grunkle Stan died and immediately go back to Gravity Falls.
• Summer, Idle no More: Stan turns out to be alive and the twins decide to stay in town for two weeks to solve the mystery of the two glowing blue cylinders they discovered.
• Old and New Faces: The Warlock is introduced.
• Identity-exe Not Found: Dipper's feeling for Wendy return. Mabel accidentally zaps Tambry with the blue cylinders and reveals her to be a high-tech robot, getting a third cylinder in the process.
• Classic Rock: The twins accidentally steal the Starkissed Stone of Conservation. Mabel contacts Fire itself and Fire sends a phoenix to help. The next episode, Birds of a Feather, introduces Harpy siblings Jace and Jess, who are tracking the phoenix to prevent the species from going extinct.
• Strongholds and Serpents: A cursed board game briefly brings Bill back. A new Zodiac with nine symbols is revealed. Dipper admits his returned feelings for Wendy.
• The New Circuit and The Town That Time Forgot: After (nearly) everyone in town is revealed to be a robot like Tambry, the Alien creators return. The twins sneak onto the ship, and, with the help of an alien known as Yuki, reverse the effects of Yuki's experiment-gone wrong. Yuki stays on Earth and the twins opt to stay in town for the entire summer. The Warlock calls his master and tells him that they should look into the town.
• Totally Real Paranormal Mystery Show: Dipper becomes suspicious of Wendy and believes she is hiding something.
• The Warlock Returns: The Warlock tries to make a move at a business convention, but gets arrested.
• Ashes in the Sky: The Phoenix crashes in town due to a pop-up storm. Manly Dan leads a mob to get the Phoenix and it's ashes. The Phoenix flies into the rain to protect the Manor but is killed by the rain.
• Summerween Returns: Wendy is revealed to be a wraith, Zander is revealed to have a hidden String Theory wall in a hidden room of his house with TONS of information, and the Warlock escapes jail.
• I Dream of Deals: Bill offers Dipper a cure for Wendy but is refused. The Warlock offers Yuki a deal.
• After the Shadows: Omir is killed and Yuki is revealed to have taken the Warlock's deal. He is kicked out for being a traitor, Zander commenting that he didn't expect that while he stares at his String Theory wall.
• Fires of Hate: Omir turns out to be alive and is revealed to be the Warlock's master. Dipper gets hurt while trying to get even with the Warlock. Yuki comes in to protect Dipper and gets even more injured before he is able to kill the Warlock.
• Cleansing Rain: Yuki goes into a coma to heal himself for the next lifetime. The Guardsman fixes Dipper. The Warlock is revealed to still be alive.
• Broken Earth and Winds of change: There is a war in town, which is eventually revealed to be a distraction so Omir can bring the Stone and Portal together. Omir's mission is revealed to have all been a trick by Bill, who leaves just as the Portal starts exploding. The twins, Soos, Wendy and Waddles barely make it out of town before it, and everyone present, is removed from existence. The Guardsman is revealed to be Zander. A young Ford is put back in the real world.
• Spectral Revelations: Young Ford catches up with the twins, Soos and Wendy and joins them on their mission.
• Montana Jeffreys and the Last Arc: We get some backstory on the Warlock when he meets Montana, his hero. The Warlock kills Montana (and over a dozen police/civilians) after discovering he helped the twins.
• The Rising Grasp: The twins, Soos, Wendy and Ford team up with the Guardsman and his students. His students learn he is actually Zander Maximillion. The Warlock appears to shoot Zander dead, but captures him and takes him in a helicopter when he realizes the truth: Zander is a wraith.