4 high school students find themselves in three different time periods: one is in the past, two are in the present and the last is trapped in the future.

I think that is pretty good Debbiemoon:-- four students become trapped in the same house, but in different time periods?

Then maybe: --"They must find a way to reunite or be trapped in time forever"

Okay, so clearly the house is a major element. So you probably need to reflect that in the logline - "four students become trapped in the same house, but in different time periods" or something better than that.

You could give more clues to tone, too. This could be anything from violent horror to time-travel comedy at the moment. What's at stake? What's the key to getting back together?

Yeah, it was kind of vague but I wanted to know about the originality of the plot before I started writing. It's about 4 students that become friends over a school year and one night go to one person's house. In the house the time period changes, as I mentioned. So they could all be in the same room but never see each other because they are in different times. After this happens, they have no idea what actually happened and that's what they must figure out. They need to find each other and find out why and what actually caused the change in time.