Everything is going great until weird things start happening in the house, all of which coincide with little Kristi suddenly having an imaginary friend who she calls Tobey. She speaks to him in the corner of her room, just to the side of a video camera that Dennis has placed there, as well as elsewhere in the house, in attempts to record those odd occurrences.

As he continues to capture them on tape, he and the rest of the family slowly start to realize that something supernatural and potentially quite dangerous is escalating in their home.

Storytellers and filmmakers have long known and utilized that human condition, especially when it comes to horror tales and movies. After all, think of many of the greatest and most effective ones -- such as "The Exorcist," "Poltergeist," "The Shining," and "The Omen" -- and they all involve children who end up threatened by one sort or another of supernatural entities.

The filmmakers behind "Paranormal Activity 3" use that tactic first and foremost in this second sequel to the ultra-low budget but surprisingly effective original film that director Oren Peli and studio Paramount Pictures unleashed on viewers back in 2009. Inspired by the success of the "found footage" flick, "The Blair Witch Project," the original "PA" started out quite small and turned into a monstrous surprise hit. Not surprisingly, it spawned the 2010 sequel, and now this offering.

For most horror films (or those of any genre, for that matter), the higher the number of the sequel, the worse or at least the weaker the resultant film. Bucking that trend, this is a taut, tight and quite short (at 80-some minutes) pic that mixes haunted house type "fun" scares, really effective jump scenes, some truly unnerving moments and, of course, not one but two children who end up in perilous situations.

Following the trend of some higher numbered sequels, this one goes back in time to be a prequel to the events that occurred in the first film. All of which means that the adult sisters in the preceding films (Katie Featherston and Sprague Grayden) have now been replaced by Chloe Csengery and Jessica Tyler Brown as much earlier incarnations of those characters, with both having different style run-ins with the latter's "imaginary" (and mostly invisible) "friend" named Tobey.

The overall premise, however, is pretty much the same as before. Weird stuff starts occurring and surveillance style cameras are set up to capture whatever that might be. As in the "PA" predecessors, new directors Henry Joost & Ariel Schulman (who did "Catfish" together) use the latter to keep the viewer's interest highly focused on the screen, as you're never sure what's going to move, pop out or otherwise provide a jolt or creepy moment. But they also utilize a new trick by having the resident videographer (Christopher Nicholas Smith) put an old VHS camcorder atop the post of an oscillating fan to create back and forth surveillance footage.

That tactic allows the directors and screenwriter Christopher B. Landon to get a lot of mileage out of goosing the viewer by showing part of the kitchen, only to have the camera then slowly pan away into the living room, stop, and then pan back again, all of which incredibly ratchets up the tension, suspense and goose bumps. Scenes featuring a figure under a sheet and another involving the kitchen furniture will surely get viewers going.

Like before, part of that fun is listening to the crowd react in delighted fear, knowing full well the filmmakers are purposefully manipulating all of us. Accordingly, the flick will play far better on the big screen, where the rapid eye movement scanning will also provide a much greater optical workout as compared to when everything gets condensed onto much smaller TV screens.

If there's one complaint, it's the "surprise" revelation at the end (designed to explain everything that occurs here as well as in the later/earlier films) that may spook some but could feel a bit hokey to others. And the characters still inexplicably keep running around shooting video even in the most horrifying moments and somehow don't have the common sense to turn on house lights (a few simple script tweaks could have remedied both issues).

But those are just small complaints as the film, for the most part, works quite effectively it what it tries and wants to be. And that's a taut horror ride with enough thrills, chills and gotcha moments to keep audiences asking for more. All of which means the "Paranormal Activity" series will likely continue to haunt movieplexes and viewers for a number of Halloween seasons to come, especially if they keep up with the kids and supernatural material combo. The third installment rates as a 6.5 out of 10.