The first episode follows Nick and Chelsea from Idaho, whose twin daughters Callie and Carter are joined together at the sternum. The programme meets the family as the twins approach their fourth birthday, and their parents face the agonising decision of whether to put them through complex surgery to separate them. To help them make this fateful decision, the family heads on an emotional journey to meet other conjoined twins and their parents.

The Torres family also find out how 18-year-old twins Sohna and Mohna from Amritsar in India cope being joined together. These twins have got over people staring at them and are training in electrical engineering observing that having four hands means they can work more quickly than others. They are healthy and happy - although they rule out getting married at the moment.