As Halloween descends on Sin City, the CSIs investigate when a creepy mannequin prop inside a popular haunted house turns out to be a real dead body. Also, Catherine enlists…

After all the guests attending an upscale fundraising soiree for the science department at a local university fall ill, the CSI team gears up to investigate. Also, Catherine enlists Grace’s…

Catherine’s frustration intensifies when a lead suspect in Grace’s disappearance is found murdered. The team exhausts all their skills to figure out who killed the suspect, and if his death…

Tariq, finds himself on a quest for normalcy, which is not in arm’s reach as he returns to school and attempts to find evidence of his innocence. Helping Tariq, as…

After Monet’s agreed to do business with him, Tariq initiates his play to control the drug market on campus, while insulating his and Monet’s involvement.

Tariq’s hands are tied, fearing that fully letting Brayden in on their arrangement with the Tejadas has put him on a violent collision course with Cane, who demonstrates the price…

After the head-on collision of Tariq’s worlds at Homecoming, the campus is hot, causing problems as he tries to settle up on debts.

Tariq St. Patrick adjusts to the changes that were prompted by a dramatic change in how his world is operated, which includes the death of his father and his mother…

Tariq struggles with the weight of providing for his mother’s mounting legal defence while juggling the rigours of Ivy League life.

Sporting a new hairdo and attitude, Kinsey takes a chance with Scot by sharing what’s going on inside her head. Tyler tries to impress his crush.

Kinsey uses a key to seek vengeance on a school bully. A troubled Nina finds a sympathetic ear. A long-buried memory casts Rendell in a new light.

Kinsey explores the sea cave with the Savini Squad in tow, Nina confronts Ellie over Joe, and Tyler sabotages his relationship with Jackie.

Tyler and Kinsey feel torn when they figure out why Nina is acting strangely. Bode meets Rufus and Ellie’s houseguest. Dodge zeroes in on the Omega Key.

As pieces begin to click into place for the Locke siblings, Ellie opens up about her connection to Dodge, and Kinsey comes clean with her friends.

The battle over the Omega Key leads to decisions that can’t be undone — and a dangerous door that promises plenty of trouble ahead.

After the Lockes move into Keyhouse, Bode makes a new acquaintance — and a startling discovery. Tyler and Kinsey try to start over at a new high school.

While Nina uncovers details about Rendell’s past, Kinsey helps out the Savini Squad, Tyler falls in with a bad crowd, and Bode finds another key.

Locating a powerful new key sends Bode’s spirit soaring. Tyler’s simmering rage boils over. Kinsey realizes just how much her fear is holding her back.

Determined to regain control of her life in the aftermath of Noah’s death, Isobel makes a risky choice despite its potential consequences. Alex and Michael work together to unravel the…

Liz’s work to find out more about a found skin sample hits a roadblock. Meanwhile, Michael continues to gain Bonnie’s trust, but Clyde may not be as easily persuaded. Also,…

After uncovering a devastating secret about Rosa’s death, Liz takes matters into her own hands to protect herself and those around her. However, her plans are sidelined after a day…

The Fosters and the Hunters get together for a Dutch-themed goodbye party for Brandon and Eliza.

The Fosters and the Hunters help out with the impromptu volunteer Christmas event. Stef agrees to be a part of Mariana’s plan to avoid a major catastrophe, all while Gael…

The Fosters visit the Coterie for Christmas and Callie struggles to tell her moms about quitting her clerkship. Mariana agrees to volunteer for a holiday festival for the underprivileged. Alice…

Willis defies Campbell’s orders when he helps Mario and Heather perform a radical procedure on a maintenance worker stuck under a boiler that exploded. Also, Angus’ father, Dr. Desmond Leighton,…

With Emily by his side, Daniel goes toe to toe with his fiercest business rival, Jason Prosser, to land an important deal that Victoria is determined to block. Aiden takes…

With Emily by his side, Daniel goes toe to toe with his fiercest business rival, Jason Prosser, to land an important deal that Victoria is determined to block. Aiden takes…

Ignoring Paul’s and Oliver’s objections, Luke and Bess come up with a plan that will alter their family structure and dynamics.

Paul attempts to put Oliver’s mind at ease, and his parents have had a hard week which they can now put behind them.

As Bess readies for a well-needed vacation, she gushes over how well Oliver has done, but Paul is skeptical that her son could not have changed that quickly.

Bess swings by Paul’s office to pick up the turtle that Oliver left behind. She explains that her son has been staying with Luke for the week, giving her some…

Sixth-grader Oliver sits with Paul in his office while they wait for Oliver’s mother Bess to return from the deli and for his father Luke to arrive. Oliver suggests they…

Oliver and Paul talk while Bess and Luke wait to be invited in. Oliver says he doesn’t want to talk about school because all of his teachers hate him because…

When the CSIs investigate who or what caused a horrific car accident, both drivers’ darkest secrets are revealed.

When Lily’s ex-husband, Dr. William van der Woodsen, shows up unexpectedly in Manhattan, Serena finally gets the reunion she has so desperately wanted with her father, but the circumstances turn…

Will’s return to the Upper East Side continues to stir up problems for Serena, Lily and his long-standing rival, Rufus. Serena and Jenny’s relationship is strained as a result of…

When things get tense between Rufus and Will, Serena chooses to stand behind her father, while at the Rufus is made to feel like an outsider in his own family….

On the anniversary of Bart Bass’ death, Chuck wrestles with an issue from the past and a serious car accident rocks the Upper East Side. Dan and Vanessa attempt to…

Nate and Serena decide to explore the boundaries of their friendship. Blair suspects that Chuck is having problems forgetting about the woman he saw at his father’s grave. Jenny agrees…

“The Wall” is the seventeenth episode of the fourth season of the NBC science fiction drama series Heroes, and the seventy-sixth episode overall. The episode aired on February 1, 2010.