Graceless - Series 1.1 - The Sphere

The Sphere is a private satellite complex and offers every kind of entertainment. It doubles in size every week. They lash new hotels and casinos to the outer skin, pinning them in place with huge girders. Zara came here by mistake and was quickly caught up in the noise and excitement. It's got into her head. When her sister Abby comes to the rescue, Zara insists that she can't leave. What is the secret that Zara is carrying with her? Why is Abby so ill? And how long can she resist the Sphere getting into her head as well?