Alone on screen for most of the film, Game of Thrones’ Iwan Rheon does all the heavy lifting in this low-budget sci-fi thriller.

The setting is a futuristic Earth, 57 years after an alien invasion forced most of humanity underground, and Rheon’s lone soldier, S.U.M.1 (‘someone’, geddit?), is guarding a defensive watchtower against extraterrestrial attack.

As his 100-day mission wears on, though, solitude and paranoia begin to crack his gung-ho spirit, and are there really any aliens out there..?

This is hardly new territory for a sci-fi filmmaker and Berlin-based director Christian Pasquariello gives us little that’s particularly distinctive or original here. However, Rheon does his best in an underwritten part and there is the odd flurry of worthwhile action towards the end.