Castor pursues the Leda clones for original tissue samples. Helena, who is pregnant and imprisoned, is examined by a mysterious new villain. The Castor boys are also out to play, toying with a frightened young woman, Patty, in a sexy switcheroo that ultimately sets Sarah – and Art – hot on the Castor trail. But it’s not all fun and games for the Castor boys, as Sarah gleans they may have a mysterious defect that puts their lives in peril.

The episode was rated 7.65 from 1991 votes.

Leda and Castor are both on the hunt for original clone DNA. On-the-lam, Mark and Gracie pursue new leads to find the samples that might set them free, while Art and Sarah reunite to track them down. Meanwhile, Cosima and Scott try to learn more about Castor’s biology and 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.

The episode was rated 7.74 from 1923 votes.

Helena and her seestra are reunited at the Castor camp when Sarah is captured. As Sarah suffers testing, Paul appears to chide her; but his allegiances are beginning to strain. While the Leda family worries about Sarah’s absence, Gracie ‘breaks Amish’ under the care of Mrs. S and an unwilling Felix. Cosima falls hard for an internet date, Shay.

The episode was rated 7.75 from 1789 votes.

Mark is taken down in a Prolethean shoot-out and Sarah must step in to help. But as Sarah gathers intel that puts her on the trail of the original Castor DNA, a familiar foe is not far behind. While Helena continues to toil in a faraway military compound, it is ultimately Sarah’s fate that will hang in the balance as she tries to save her sister. Meanwhile, Gracie is cast out from the Prolethean fold, and Alison and Donnie come face-to-face with unhappy drug lord, Jason Kellerman.

The episode was rated 7.75 from 1766 votes.

Sarah pursues the missing Helena who is held in a faraway compound. Sarah must use 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. But when the menace of Castor rears its head once more, Sarah and her entire family must come together to survive.

The episode was rated 7.77 from 2325 votes.

Alison must secure a store front in order to take her and Donnie’s business to the “next level”. But things don’t go according to plan when her mother, Connie, proves to be a major hindrance. Cosima is facing familiar health issues and calls upon beleaguered Alison for a favor. But with Alison working to save an imperiled Donnie from the merciless hands of a drug lord, it’s Cosima who ends up doing a favor. An unassuming Scott gets closer to the greatest discovery of all, when he sits down with beleaguered clone Rachel.

The episode was rated 7.90 from 1818 votes.

When Rachel makes a promise to Sarah, it comes with a hefty price. Meanwhile, Helena and Gracie work with the Hendrixes, and Donnie takes Kellerman to task. Over at Castor, Coady and Benchman scheme to track down the Castor Original, and Rudy descends on DYAD for a much needed asset.

The episode was rated 7.97 from 1823 votes.

Sarah, Felix and Mrs. S take a trip with the hopes of tracking down the Castor Original. But they are not alone. Back home, Donnie tries to save the family business when Pouchy defects, but it is Helena who manages to secure a “full refund.” Meanwhile, Cosima becomes suspicious of Shay, and Delphine takes the matter into her own hands. But nothing will ever be the same again when Leda finally finds what they’ve been looking for.

The episode was rated 8.03 from 1847 votes.

Paul digs and finds the ugly truth behind the Castor Boys’ logbooks of names, pushing him into action. Meanwhile, Felix is desperate for info on Sarah’s whereabouts, and presses 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 introduce Jason Kellerman to her unique business plan.

The episode was rated 8.10 from 1938 votes.

As Clone Club races towards the truth, Castor and Topside force Sarah to make uneasy alliances. Meanwhile, Kendall may be the key to stop Castor; the sisters appear to be thwarting their most dangerous foe.

The episode was rated 8.26 from 1948 votes.