In this game you play as Commander Sheppard. You will uncover massive conspiracy, force truce between AI and organics, have lots of huggy wuggy time, participate in bottle shooting competition amongst many other cool things.

Things, that don't matter in the end...

Still, this package of 3-in-1 games is a very good deal. For co-op experience buy original game (ME3) or Andromeda (yes, I am serious).

By the way, to spice things up for another hundredth time, I highly recommend this guide - https://www.nexusmods.com/masseffectlegendaryedition/mods/1127