This battle takes place at the former Zeon base known as A Baoa Qu.
For the Close Range portion of the battle you'll get to control Apolli's Rick Dias and Emma's Gundam MKII in addition to the Zeta Gundam. Remember all of that leveling up you did for the MKII in Mission 17? All of that time you spent amounted to nothing because the Rick Dias and MKII are at level 18 regardless of past levels. Be sure to press the R Button to access the Rick Dias.
First up to bat will be two squads of three Barzams each, followed up by two squads of three Marasais each, and finally two squads of three Hi-Zack Customs each. There, got all that out in one shot.
Once the above have been defeated Sara comes out to fight you again. This battle isn't hard but it isn't exactly easy either. The Bolinork Samarn (like previous suits) is a new model meaning that it is suppossed to make the others look like nothing, and like always the new model doesn't "cut-it".
The Bolinork Sarman's attacks are very powerful dealing about 50AP damage per hit, but luckily it lacks in the speed department. When you get your turn, however, you'll realize that the Bolinork Samarn will begin moving about at lighting fast speeds. Luckily your goal here is to inflict 1000AP of pain.
In the Close Range portion you'll notice that you have 3 mobile suits and 9 areas to cover. The screenshot to your right shows a recommended path to move your mobile suits in to quickly eliminate all enemy units. In my game Yellow was Zeta, Purple was MKII, and Green was the Rick Dias. Of course, you could always just give the Zeta Gundam 16 Energy-Pacs and let it take care of all the areas, but where's the fun in that?
The Purple mobile suit will have to fight 2 each of the Marasais and the Barzam in are 19-5. After disposing of the enemies six more of whatever type you defeated last will fly in (the +6 in the enemy table). Destroying all of these will cause Kamiyuh and the Zeta to fly off.
To be absolutly honest this battle is ridiculously easy; the Long Range battle was much harder. My favorite tactic to use is to attack once with the and then follow it up with a beam saber attack. The damage should total up to 1000AP or better which cause another set of events to be set in motion. Apolli flies in to (I'm assuming) to protect Kamiyuh but is destroyed by the Bolinork Samarn.
Meanwhile, Katz has found Haman and Scirocco battling in mobile suits and proceeds to attack. Sarah in her Bolinork Samarn get in the way of the blast to save Scirocco's life. Afterwards A Baoa Qu is destroyed and you get to watch it blow!