This episode is a play on the phrase "chasing the dragon", which was/is a way for people to ingest heroin without injecting it- It is simply a method of smoking the drug on a piece of tinfoil that requires a certain amount of finesse, otherwise money is wasted.
But here, there is a batch of dope floating around Vancouver that is literally turning people into a dragons... at least temporarily.
We are given a fairly accurate look into the lives of people who use this. With the typical Millennium twist of horror.
Meanwhile, at Quantico, agent Hollis is sitting there doing her business. Until her SAIC approaches with an entourage, basically accusing her of using, without even asking her about it. She is censured and told "not to leave town", which of course she does immediately.
After this we get to see an accurate look into the lives of addicts, what they to for the next fix, the scumbags they have to interact with, and the horrible places where they have to live in order to get clean.
But behind all of this there is some kind of insidious activity... what is causing addicts to physically change into monsters? And some of them actually want to be changed. However, the triad in charge of supplying the drug to their users does not like what is happening, and of course tries to make evidence, and bodies, disappear.
Which is where Hollis, aided by Frank Black enter in. At first Frank is skeptical when talking to Hollis's half sister, he doesn't believe her. Until of course, a body is found. A body that has evidence of having ridden a monster.
The person who wrote this definitely must have had some experience with the subculture of drug use. Everything is accurate.
More of a cautionary tale than anything else, The interesting part is what has been causing people to turn into monsters... and the person who was responsible. Of course, Hollis is reinstated with no apologies from her SAIC.