Matthew arrives at Benjamin Harrison as a sub, inexperienced and unaware of what he's in for. Fed up with a lack of chalk and erasers, Sara keeps pressing for her transfer to another school -- one that's willing to pay for school supplies. Harry tries to help a failing gang leader, Julio, whom he wants to see get into college, but Jack's refusal to change Julio's history grade -- and Julio's not wanting it to be changed -- stand between them. Joe fights tooth and nail to prevent Benjamin Harrison's day care center from being shut down when the conservative school board decides that it glamorizes -- and encourages -- teen pregnancy. Matthew tries to teach, but the students just laugh at him and walk out of his classes... even after he follows Gus' advice on how to get them to stay. Sara demands Joe sign her transfer after a student swipes her copy of ""David Copperfield"" and refuses to return it. Like Sara, Matthew threatens to quit himself when the students turn him into an impromptu da