This is the second installment in the Harry Potter franchise. It sets the mold for all that follow.
The first installment, "Harry Potter and the Sorceror's Stone," introduced all of the main characters, but did not quite get to establishing the triumvirate of Daniel Radcliffe, Emma Watson and Rupert Grint as the foundation of everything. This film does that.
In brief, Harry ignores warnings not to return to Hogwarts, only to find the school plagued by a series of mysterious attacks and a strange voice haunting him.
Forced to spend his summer holidays with his un-cool relations, Harry Potter is shocked when he gets a surprise visitor: Dobby the house-elf. Dobby warns Harry Potter against returning to Hogwarts. Apparently, terrible things are about to happen there.
Harry ignores Dobby's warning (go figure) and continues with his scheduled return. He finds that strange and terrible things indeed are happening at Hogwarts. He hears mysterious voices from inside the walls, muggle-born students are attacked, and a message scrawled on the wall in blood puts everyone on their guard - "The Chamber Of Secrets Has Been Opened. Enemies Of The Heir, Beware."
This is generally considered a better film than the first one. That isn't too surprising, they started to figure out the formula and pounded it out.
The kids are a bit older, though they still are kids. Their acting is somewhat improved, though not much.
There are the usual colorful scenes, and lots of Halloween imagery. You pretty much know what you are getting when you enter a Potter movie, as you do when you go to McDonalds.
This is a great film for fans of the franchise. You must see it if you have read the books. It did not get nominated for any Academy Awards through some oversight.