Testing Jetpack featuresAn exotic visitor sparks mixed reactions in the firehouse. Tommy deals with the possibility of expulsion from the FDNY and a new sponsorship role in AA. As Mike and the guys renovate their new bar, Sheila learns that being a big sister isn't always easy.
As animal rights activists ransack a laboratory, they get more than they bargained for when one of the caged “animals” unleashes a ferocious appetite. Leaving grotesquely mutilated dead bodies in its wake, the scientifically engineered beast with the body of a lion, claws of an eagle, fangs of a viper, skin of a rhinoceros and tail of a serpent attacks Charlie. With Charlie’s life on the line, Walter must come face-to-face with both his past and the beast.
Castle and Beckett look into the Vudon religion when an immigrant is found tortured in a ritualistic killing. Meanwhile on the homefront Castle must deal with the possible homecoming of Alexis’ mother, his first wife.
Ted goes out on his own as an architect and hires an intern to help get things started, but the intern gets a little too close to others in the gang.
As Nathan, Claire, Peter and H.R.G. help Angela uncover her past, she reveals the dark secrets that have haunted her for years. Meanwhile, Mohinder learns of his father’s involvement in a long forgotten government operation.
Jack Bauer endures the elements and fights on to prevent an attack that could change the country forever. As the catastrophic blow to the nation nears, Tony Almeida operates from the field and Kim Bauer, who was last seen in Season Five, returns. Meanwhile, the stakes are raised when the administration is faced with a blackmail scenario.
Walt returns to work. Skinny Pete gets ripped off and when Jesse steps in to “handle it,” he gets more than he bargained for. Skyler finally gets to thank Gretchen for paying for Walt’s treatment.
When a traitor is discovered inside the Dollhouse, Echo and Sierra are programmed as spy hunters to uncover the culprit. Meanwhile, Ballard receives surprising news from Mellie, and Adelle harbors a secret.
Cal and Gillian assist FEMA in their investigation of a building collapse and uncover a massive cover-up. Meanwhile, a billionaire asks Ria and Eli to determine if his girlfriend loves him for the right reasons before he proposes.
Tommy copes with the loss of his father and a new man in Janet's life. Sheila finds a different way to deal with her issues while Sean, Franco, and Mike concoct a surefire way to get rich and laid.