Climb the crack on the right side of the arete till it runs out, then move left, hug the arete and edges on the right to the top. It's really about a five move boulder problem to the top from where the crack runs out.
This route starts on the ledge above Prime Rib and runs up the arete above Bloody Mary. You can drop a top rope on Bloody Mary into Tharsis.
The top rope anchor is easy to set up. There is a ledge to stand on (accessible from the top also) with a horizontal crack in front of you.