Chris's teacher wins the lottery and is replaced Brian. Brian is moved to another class that is full with students with low expectations. Brian teaches them to aim just a bit higher.
Brian is replaced by a flamboyant and sexy new teacher, Mrs. Lockhart. Mrs. Lockhart warms up to Chris and says she will be his. All he has to do is kill her husband. Chris decides that he can't do it, so Mrs. Lockhart lets a bear into the house, who kills her husband.
Stewie and Lois find a note in Chris's shorts while doing laundry that is the detailed instructions on killing her husband. Not knowing that Chris didn't do the deed, Stewie and Lois set out to confront him.