This is part of the morituri pack. From the main menu go to the gladiator tab > custom match > solo > Beacon
This map starts with you having to kill some Barvarian guards. there will be about 4 of them. Then you will have to free the hostages, there will be 3 of them around the map. Kill the remaining barbarians and move on. The next step is to cross the border and light the beacon. Hold of against the Barbarians for around a minute or two before moving on to the next objective. hold down the left flank, by standing on the platform and killing Barbarians. keep killing barbarians untill it tells you to kill the leaders. Kill the leaders and the mission will finish.
*Thanks to A Lazy Susan it is possible to get this in arena in the Barbarians at the gate playlist. this will allow you to play the map co-op.
*Barbarian numbers may vary.
Please tell me how I can improve my solutions in the comments, thanks!