Night Fall: Coop captured Master Yo for The Night Master. Yin and Yang seek help from Roger Jr. and Carl help. But when it seems Carl can't be trusted, Coop offers to help the heroes search for the broken Toilet Brush of Illumination so the students can defeat The Night Master.
Who Knows What Evil Lurks: The Night Master wants Coop to spy on the students to know what they are thinking. But when The Night Master hears what Yang thinks of him, he grows angry and shoots a beam out of the phone to hit Yang. Now the students know The Night Master has a spy. Yin and Yang use the Chronologicum to travel through the time stream to see if they can figure out who the spy is. However, the Chronologicum gets damaged, and Yin and Yang are separated in two different times.