Sarah tracks down an elusive new ally and unearths the next aspect of the Neolution's agenda.
In the fourth season premiere, a Neolution attack destroys Sarah's refuge in Iceland and forces her to flee once again.
While Noah seeks out Tommy, Hero Truther captures Taylor. Meanwhile, Luke and Malina are separated, and Joanne and Emily are reunited.
Noah and Quentin break into Renautas and meet Miko and Ren. As they make common cause, Quentin meets his sister. Meanwhile, Tommy takes Emily to Paris, and Malina rescues Luke when he tries to kill himself.moreless
While Noah and Quentin target Renautas with their new ally, Miko tries to recover her father's sword. Meanwhile, Carlos finds an ally in his quest to fill the role of El Vengador, and Agent Cutler goes after Tommy.moreless
Malina and her mentor travel south from the Arctic Circle to save the world. Meanwhile, Quentin and Noah find an unlikely ally to help them get into Renautas, Miko and Ren arrive in America, and Joanne discovers Luke's s secret.moreless
The head of Renautas, Erica Kravid, continues her campaign against the Evos. Meanwhile, Noah and Quentin continue searching for answers, and Brady makes sure that Tommy is popular at school after Tommy makes Brady's stepfather disappear.moreless
Paul finds the ugly truth behind the Castor Boys’ logbooks of names which pushes him into action. Felix is desperate for information on Sarah’s whereabouts so he pressures the still-ailing Rachel for any shred of a lead. In order for Donnie and Alison to take their money-making endeavor to the "next level" she must convince Jason Kellerman that her unique business plan will work.moreless
Sarah must step in to help when Mark is taken down in a Prolethean shoot-out. As Sarah collects intel putting her on the trail of the original Castor DNA, a familiar foe is not far behind. Helena continues to toil in a faraway military compound but it is ultimately Sarah’s fate that will hang in the balance as she tries to save her sister. Gracie is cast out from the Prolethean fold. Alison and Donnie come face-to-face with an unhappy drug lord.moreless
Leda and Castor are both on the hunt for original clone DNA. Mark and Gracie still on the lam pursue new leads to find the samples that might set them free, while Art and Sarah reunite to track them down. Cosima and Scott attempt to learn more about Castor’s biology. Alison’s new money-making venture is going gangbusters. A shocking revelation about the Castor-Leda connection leaves the sisters reeling, just before Sarah witnesses a deadly Prolethean-Castor face-off.moreless
Season 3 begins with Sarah pursuing the missing Helena who is being held in a faraway compound. Sarah uses her wiles and acting chops to deter a Topside investigator who threatens the Leda sisters' lives. Meanwhile, Cosima appears to be rebounding from her illness, while Alison and Donnie face newfound financial woes. When the menace of Castor rears its head once more, Sarah and her entire family must come together to survive.moreless
Season 2 ends with Sarah being forced to concede when Rachel launches her latest ploy. However, the Clone Club springs into action to save her. Later, Sarah meets a new ally and uncovers a terrifying new dimension to the conspiracy.moreless
Sarah becomes frantic when Cosima's health take a down turn, but her actions have heartbreaking costs for the others. The Proletheans implement their fundamental plan. Complications with the law involve Alison and Donnie.moreless
Sarah joins forces with an unlikely ally, when she follows a trail of clues that she hopes will lead her to the origins of the clone experiment. Meanwhile, Cosima and Delphine make a discovery that could prove to be the key to treating Cosima's illness.moreless
Rachel goes on the warpath and lashes out at Sarah's loved ones. While Sarah tries to keep them safe, an unexpected visitor threatens to derail her plans.
Sarah comes home to search for answers and with Cosima's help she digs into the origins of the clone experiment. The hunt takes her into perilous territory that could cost her more than she realizes.moreless
While Alison struggles with Aynsley's death and Cosima grapples with the worsening symptoms of her mysterious sickness, Sarah enlists Art's help to find Kira and is shocked when she learns where the trail leads.moreless
With Sarah out of options, she's on the run and being tracked by deadly adversaries. She suspects that pro-clone Rachel is behind the disappearance of Kira and ignites all out war against her. Allison sinks into guilt and depression after attending Aynsley's funeral. Cosima is confronted with a decision that could have calamitous results.moreless
The Huntress returns to town to kill her father, who has been arrested. Oliver promises Sara that he'll stop his ex-girlfriend. However, when Huntress takes a courthouse hostage, including Laurel, Sara steps in. Meanwhile, Roy realizes the cost he must pay to keep Thea safe.moreless
Laurel reaches out to Arrow for assistance in investigating Sebastian Blood, but he has her arrested for her drug use when she gets too close to his secrets. Meanwhile, Roy almost kills a man when he loses control of his newfound strength. In the past, Sarah tells Oliver a secret about her older sister.moreless
A new villain, Shrapnel, arrives in Starling City and his next target is Sebastian Blood. With Arrow trapped, Diggle must try and help the alderman. Meanwhile, Thea learns about Roy's new abilities and Laurel investigates the connection between Blood and Cyrus Gold, the man who murdered her father's friend.moreless
A deadly illness sweeps through Starling City. When Diggle is struck down, Oliver confirms that the source of the illness is a new version of Vertigo. Tracking down a lead, Felicity is soon captured by The Count, who has escaped prison. Meanwhile, Moira fights for her life in the courtroom against a death sentence, and Laurel is forced to prosecute her when DA Donner is stricken down by the same illness.moreless
An assassin attacks Queen Manor in an attempt to kill Black Canary, who has taken refuge there with Oliver's help. Meanwhile, Moira is reluctant to make a guilty plea despite Thea's advice, and Oliver is furious when he discovers that Laurel will be prosecuting his mother in court.moreless
A new crime lord, the Mayor, arrives in Starling City and starts bring in illegal guns. When Oliver tries to counter with a Cash for Guns event, Black Canary's friend sin is hurt and the female heroine sets out for revenge. Meanwhile, Diggle links up with an old friend and DA Donner asks Laurel out on a date.moreless