The Halo Legends anime series been given a February 9, 2010 release date according to the official website. You'll be able to watch each episode on Halo Waypoint (on Xbox LIVE) for a 24-hour period each. There will be 7 short anime films in all, The first screen was The Babysitter, the second was The Duel.
The plot is basically, a team of ODST soldiers must provide support to a Spartan CAL 141 who's mission is to put a sniper bullet in the head of a covenant Prophet. The question is, who is babysitting whom?
Longer version of the plot:
The squad enters the asteroid ring surrounding an unnamed planet in their drop pods, losing Checkman in the process; his pod bumps into an asteroid which knocks him off course, sending him plummeting into the planet the wrong way.
The other four pods land on the planet in close proximity to each other; Cal, Dutch, and Cortez land in a forest, and O'Brian lands in a swamp. Dutch and Cortez go to get gear to retrieve O'Brian, but stop when Cal simply walks into the swamp, unphased by the thick mud, and lifts the drop pod out of the mud, throwing it to the side. Thus the 'baby' saves the ODST trooper.
Dutch tells O'Brian that Cal singlehandedly saved him from certain death, and his contempt for the SPARTAN is obvious.
The ODST squad plots out the mission: the Prophet will be landing at a logistics site north of their landing zone, and they need to get there before it does to set up for the sniper shot, but before they can do that, they need to photograph the ruins on the way to gather intel.
When they arrive at the ruins site, Cal halts them, noticing a patrol of Unggoy and a Brute Chieftain. The SPARTAN orders them to take out the patrol covertly; Cal kills a grunt with a knife, Dutch knocks another one out, whilst Cortez breaks one's neck.
As O'Brian prepares to sneak up on his prey, he gives away his position by stepping on a twig (that old movie cliche!) , and the nearby Chieftain also notices. The Chieftain moves to smack O'Brien with his gravity hammer as he takes out the grunt with his SMG, only to be stopped by Cal, who grabs the hammer before is nails O'Brian.
In the resulting struggle, O'Brian dangles from a cliff, and then a waterfall, losing his sniper rifle, and is left to watche Cal fight the Chieftain in hand-to-hand combat. The Chieftain is ultimately thrown off of the waterfall, after being blinded in one eye by a punch to the face by Cal. O'Brian as he loses his grip and is caught by Cal just before he falls and carries him back to the squad. His contempt for Cal grows yet further, having been saved twice and humiliated in front of his ODST company.
Finally, the squad reaches their destination two minutes before the Prophet lands. Cal sets up for the shot, and the Chieftain, who followed them from the ruins, ambushes the squad, choosing to attack O'Brian first. Seeing the danger, Cal jumps in front of him, taking the hammer blow to the head and shoulder.
Dutch, Cortez, and O'Brian all jump in as one tackling, the Chieftain. Dutch manages to unload his SMG into the Chieftain's face, killing him.
Cortez removes Spartan Cal's helmet to assess the injuries, and to the squad's shock, they find that Cal is a woman.
The Prophet has by then landed. A dying Cal urges O'Brian to take the shot, claiming he's the only one that can do it. He hesitates, then picks up the rifle and takes the shot, killing the Prophet, and causing a major uproar among the Honor Guard at the landing site.
Back in, safe in space, O'Brian ponders the fact that Cal was a woman, that she saved him twice and in fact she was arguably The Babysitter.This the plot points of this post were basically ripped off from Halopedia with edits by myself.