I've seen the first Boogeyman before, but I'll be honest and admit I remember absolutely nothing of that film. Not even after watching this second one, so I'm not even sure how and if these two are really connected. Not that it matters a lot, this is a basic horror flick that could've been released under pretty much any other name.
Laura and Henry are both traumatized by a run-in with the Boogeyman at a young age. In an attempt to get rid of their trauma, they join an experimental program that helps people deal with their fear. It's not the most healthy environment and when the Boogeyman appears again before Laura, people are bound to die some gruesome deaths.
When you're getting Jigsaw (Saw) and Gabrielle (Xena) as doctors in a mental ward, it's immediately clear you're not dealing with a very serious film. The kills are pretty gruesome and effective, the rest is lame and derivative. Seeing as this is a core horror flick and the kills are plentiful, that's not such a bad trade-off.