From NetFlix:

In 2nd-century Britain, Roman fighter Quintas Dias (Michael Fassbender) is the lone survivor of a Pictish attack on a Roman frontier post. Eager for revenge, he joins the Ninth Legion — under General Virilus (Dominic West) — and journeys north on a mission to destroy the Picts. Writer-director Neil Marshall’s rousing sword-and-sandals adventure also stars Olga Kurylenko as the beautiful Pict warrior Etain.

There is a point to this film, something like “ET Go Home”.

Traipsing (or actually running breathlessly to avoid being eaten by wolves or slaughtered by Picts) through beautiful forests, fields, and mountains, the only thing these poor survivors of the Roman Ninth Legion want to do is leave nasty northern Britain and go home.

As usual our wanderers are superb (dare I say, super-hero) fighters who, unfortunately, for the most part eventually die. In fact, the entire film is for the most part just watching their demise, one by one.

For me Olga Kurylenko was just plain silly: lady, get a better makeup artist! Michael Fassbender was Lieutenant Archie Hicox in Inglourious Basterds (2009).

No spoilers allowed: stick around for an ending that surprised me.

For what it is worth, I give you this quote from IMDB:

German archaeologists have found evidence of the Ninth legion on the banks of the River Rhine and carbon dated them long after these events took place suggesting that rather than them being wiped out, the reason that there is no evidence of them being in Scotland after these battles is that they moved to Germany.