'Wanted: Someone to go back in time with me. This is not a joke. You'll get paid after we come back. Must bring your own weapons. I have only done this once before. SAFETY NOT GUARANTEED.'

This is the newspaper ad that inspires three cynical Seattle journalists to take the trip upstate to investigate who placed the ad. Interns Darius (Plaza - Parks And Recreations) and Arnau (Soni) are under the guidance of the experienced Jeff (New Girl's Johnson), who seems to be only on the story because his ex lives nearby. Darius is giving the job of feeling out Kenneth (Indie king Duplass), known locally as a kook, to see if he's all there, but finding that he is very sane and has very real reasons to back in time, Darius remembers that there is something in her past that needs fixing too...

More 'indie' than Looper and more accessible that the binary code dialogue of the low-budget Primer, Safety Not Guaranteed might not have the brain but boasts a lot of fun and heart than those two time-travellers. While it isn't as funny as it thinks it is - the paranoid delusions, the less-than-professional combat training by someone who thinks they are the shit when it comes to professional combat training - it's when Jake Johnson is allowed off the leash that the jokes flow.

The subplot - Johnson stalking the girl he dated back in school - at first seems a distraction from the time traveling story until you realise that's exactly what loverat Johnson is doing. He might be using Facebook to track down his one true love but it's just as much a time machine as the one Duplass has claimed he's built. This subplot turns out to be a real charmer: we all have something in our past that we'd like to do over, make right.

But as much of an admirer of Mark Duplass that I am, he feels unsuited to the jittery paranoid Kenneth. Debutant Derek Connolly's script teases us with Kenneth in every scene - Is he crazy? Are his Napoleon Dynamite-esque boasts for real? - but Duplass can't convince.

Charming and fun, this is worth checking out.