South Park 7x01 watch series online

South Park: Cancelled

The boys are at the bus stop and they seem to be reliving events that they went through 6 seasons earlier; that is Kyle "kicking the baby" his little brother Ike and Cartman talking about his strange dream, which the other boys identify as visitors.
What's going on in South Park? Did the boys travel back in time, or is some sinister force at work?