The single most frustrating DLC in the entire Mass Effect franchise. On normal difficulty it's forgivable. Arrival pits Shephard alone against an entire base full of indoctrinated Cerberus morons where 99% of this mission is just shooting room after room after hallway of dudes and eventually mechs as you try to crash an asteroid into a mass relay that the Reapers are going to come through any moment to start their invasion.

This DLC ties in directly to the beginning of Mass Effect 3 and explains why Shephard has been stripped of his rank, command and ship. It's cool but it's also just a pain and should have been included with the original game.