Phase 7, also known as Fase 7, is a film focusing on a man named Martin (nicknamed Coco by his wife) who feels that he wants to find more excitement in his life. On the drive home from the supermarket, he proposes an idea to his wife where they sell everything and start a new life out in the country. However, his pregnant wife, Pipi, can only reply to Martin's ideas with sarcasm and negativity. They arrive at their apartment complex and find their mysterious neighbor Horacio.
Before following his wife up to their apartment, Martin notices that Horacio is stocking up on goods as if preparing for a war. Just as they're sitting down to enjoy their evening meal, they are paged by some mysterious recording on their phone to send one person to the lobby of the apartment complex. Here neighbors Zanutto, Lange, Guglierini, and Horacio are found discussing the situation before them. The apartment building has been covered, and according to the South American Center for Disease Control they are all under quarantine because one of their neighbors was diagnosed with a mysterious illness and should they need anything to dial 833 for emergency assistance. Zanutto, throughout this, is covering his mouth with a handkerchief to cough into.
Martin is in for a surprise as the once calm and quiet apartment building is suddenly stricken with chaos and intrigue. Neighbor suspects neighbor as people begin to fall to the illness or display signs of cabin fever. In the middle of it all are Martin and his new quarantine buddy, Horacio, trying to survive the seemingly endless imprisonment in their own home. Will the new-found excitement Martin craved be too much for him, or will the disease claim him before he has a chance?