Fifteen Hours

Fifteen Hours is a Black Library novel by Mitchel Scanlon. Due to a bureaucratic slip up, the protagonist Larn has been dropped into an extremely hostile war zone (instead of a different moderately hostile war zone). The New Meat has been assigned the goal of surpassing his life expectancy, which is a mere 15 hours. Unless he manages to accomplish this some soldiers refuse to even bother learning his name. The novel can be found as its own book or as part of Imperial Guard Omnibus: Volume One.