Joan's in chemistry class. Man, Amber Tamblyn has some seriously pouty lips. Excellently shaped, too. Joan looks miserable. Mrs. Leschak is rambling on. Joan glances to her left, and notices Adam drawing an extremely exaggerated cartoon of the teacher as a scantily-clad dominatrix type. The teacher continues blathering on about laws of proportions or something, and after smacking the blackboard with her pointer, walks around twirling it like a baton, saying, "The chemical concepts here include single-replacement, exothermic reactions, enthalpy, and..." She points dramatically to Luke, who says, "Entropy." Everyone gasps like he just proved that the earth revolves around the sun or something. Mrs. Leschak starts marching around and chanting, "Go, Luke, go, Luke..." The class joins in. To Joan's right, Grace is fiercely carving something into the desk with a metal ruler. Probably "Fuck school before it fucks you." Luke: "Iron oxide is reduced to metallic iron by aluminum reaching a temperature of..." He thinks, and the teacher leans over his shoulder and taunts, "Need a calculator?" Luke: "No...approximately 3,000 degrees Centigrade." As the bell rings, Mrs. Leschak assigns a home test: "List the chemical equations which take place in a typical wood fire." They have to work with their groups, and it's due before the bell. Joan looks like she's planning to check into atheism at her earliest opportunity.

At the arson site, Will greets Roy: "Mr. Roebuck." Roy corrects him, "Lieutenant Roebuck." Will points out that he's a Chief. Roy: "Not my Chief." Dude, chill. Will says that if he's withholding evidence, he'll arrest him for obstruction of justice. Roy says he's just taking the time he needs to be thorough: "Your guys should try it sometime." I bet he gets great results with this confrontational, insulting approach. Girardi complains that the trail of arsonist is getting colder by the minute. Roy says, "Anybody asking questions about who might benefit from this building being burned down?" Will walks away, saying that they'll do their job, and he should do his. Roebuck has one last shot: "That's the least a reasonable person could expect."