Dipper and Mabel go trick-or-treating in the summer and encounter a candy-loving monster who threatens to devour them if they don't bring him sweet things to eat.
A woman recants a domestic-abuse claim, but Danny and Jackie continue to investigate the situation. Soon they uncover the woman's secret affair with a powerful politician who's friends with Frank. Meanwhile, Linda returns to the workforce, causing chaos at home.
In order to keep his grip on Chicago, Kane finds he has no choice but to work with Alderman Ross.
The Fringe team revisits the Harvard lab, now under Observer control, to try to find the information they need as the team fights on in their mission to save the world.
Angelina comes to town with bad news; Nick asks Hank for help keeping Monroe safe; Captain Renard receives a visit from a past acquaintance.
The Ross kids become concerned that history is repeating itself after a scary old doorman tells them a building legend about a nanny who did “something terrible” to the kids in her care on Halloween. Meanwhile, Jessie and Tony work together to crash an exclusive Halloween party so Jessie can give her short story to a famous magazine editor.
The CSIs rush to stop serial arsonist Leonard Brooks after he begins using fire against people from his dark past.
Audrey and Nathan encounter a bizarre series of deaths suggesting a serial killer, with a unique “trouble”, is at work in Haven. Meanwhile, a Boston cop tries linking the town's latest body to similar cases.
An unemployed man and his pregnant wife pitch a party-favorite chicken dip; a professional football player's spring-loaded laundry hamper, a technophobe presents his wireless gadget that helps people keep track of their keys or cell phone.
When Sheldon learns that Penny is thinking about breaking up with Leonard, he tries to intervene. Meanwhile, in space, the other astronauts pick on Howard.
Sherlock uses his powers of deduction to consult on the murder of a young man who is shot upon entering his apartment. Meanwhile, Watson has dinner with her ex-boyfriend, Ty Morstan.
Sy's spy past comes back to haunt him when his former partner returns to kill him.
In this flashback episode, return to the site of the plane crash and watch as each doctor tries to cope with the heartache and injuries caused by the crash. Meanwhile, back at Seattle Grace, everyone struggles to find a bit of normalcy amidst the chaos.
More than 20 warships close in on the Colorado; as Kendal is forced into a battle on the ground, Prosser questions Marcus' judgement
The Machine delivers the number of a cold case that leads Reese ever closer to catching up with Finch and his kidnapper, Root.
Andy flaunts his genealogy when he discovers he's related to Michelle Obama. Meanwhile, Darryl struggles in his new post, Dwight teaches Erin a new language to wow her boyfriend's family, and Nellie tries to persuade Pam that Jim's having an affair.
Leslie helps a local swim team get more practice time by working on a new law that extends the hours at the community pool; Ron finds himself filling a pothole for a local woman (Lucy Lawless) as part of Chris' new plan to solve citizens' problems around the city; April and Ben take a road trip to Pawnee.
Lorenzo decides to live life on the wild side when he meets the fun-loving, carefree Bruno. Mac is convinced Bruno is bad news, but will Lorenzo listen - or will his new attitude spell trouble for him and his friends?