The kids go on a field trip to the planetarium. All of the children except Cartman are acting weird. As usual Stan and Kyle, with Kenny's sacrifice, try to get to bottom of the mystery. Meanwhile, Cartman wins an appearance on a snack commercial. The four boys get to the root of the strange planetarium.
Elenco: Trey Parker , Matt Stone , Mona Marshall , April Stewart , Isaac Hayes , Eliza Schneider , Mary Kay Bergman , Milan Agnone , Sebastian Yu , Jessie Jo Thomas , Jennifer Howell .