What is a Log Line?

The logline is truly an art form of its own. It's the one or two sentence summary of your film that not only conveys your premise, but also gives the reader emotional insight into the story as a whole.

Look at this for inspiration: 
http://www.raindance.org/10-tips-for-writing-loglines/

Task: Write 3 ideas for loglines for a thriller. In your group of 4 analyse each students' log-line and pick three that you think will translate into the best OTS.