Dans un avenir proche, un petit groupe de soldats se retrouve coincé en mer dans un avant-poste abandonné et attend l'arrivée de la relève ou l'invasion ennemie. Qui des deux arrivera en premier ? Set in the future on a war-ravaged Earth, four exhausted soldiers man Sentinel - a remote military base in a vast ocean that separates two warring continents. While their tour of duty ended three months ago, the relief crew still hasn't arrived and as the empty weeks turn to months, paranoia descends, testing relationships to breaking point...