Les deux jumeaux Zack et Cody sont un jour approchés par un scientifique qui leur propose de participer au "Projet Gemo": une série d’expériences dédiées aux liens qui unissent les jumeaux. Mais à l'issue du projet, les deux frères se rendent compte qu'ils partagent désormais les mêmes pensées, les mêmes sentiments et les mêmes sensations.
After making plans to spend spring break with Bailey, Cody takes a job as an intern at a prestigious research firm, breaking his plans and leaving Bailey infuriated and refusing to speak to him. Zack then runs a billion-dollar submarine into Vancouver's seawall causing the equipment to get lost which results Cody being fired from the program and vowing to never speak to Zack again. While there, Dr. Olsen approaches Zack and Cody, telling them that they are perfect for the 'Gemini Project,' a massive project studying the effects of twins. After making much thought, the twins decide to participate, and land themselves among dozens of other twins. In the beginning, all seems normal, but before long, the two suddenly find themselves connected metaphysically in a way they never have been-able to before. If one twin has a thought, the other does as well; including feeling the same pain at the same time. But as their week on the 'Gemini Project' campus goes on, they soon discover that all is not what it seems, and set out to discover just what the project is really about.