This is a fine example of why this series is as good as it is. It has one of the best opening sequences seen on the series but one of the hardest as well. It is impossible to avoid thinking about that poor family which appears in that sequence and which is going to die because of the insane mind of a crazy arsonist.
I have to say that if that sequence was hard to watch, the scene when another family dies inside a car was hard as well. The story is well-written and it is clearly explained why the arsonist does what he does and why Evan Abby acts as he acts. Besides, this episode shows the viewer the humanity of both Hotchner and Prentiss and how bad does Hotch feel about Abby. A very good one to watch.