After finishing KTA4 and Phoenix I had to stuff my face with some more Ryoko maps and this came in clutch. This scenario uses no AR and has pretty unorthodox progression. Not as convoluted as the other reviews say, methinks. Also has a lot of funny references to Rubicon so maybe you might want to play this after you've played that first
A three level (plus one intro level) mini-scenario for Marathon Infinity.
This scenario is a sequel to Marathon Phoenix, although it is not as difficult. The player is reunited with Durandal, and the two follow the path of the UESC Atreides to a distant Human base.
EDIT 2/11/2014 You will probably need the Previous AI plugin to make this work! http://simplici7y.com/items/aleph-one-previous-ai