Mission 44: Eliminate the Avalanche
Mission 44 in Kingdom Hearts 358/2 Days sends Roxas to Twilight Town to defeat the Avalanche. This mission involves not only eliminating the Avalanche, but to also collect Organization XIII Emblems around Twilight Town.
 Mission assignment
An Avalanche has surfaced in Twilight Town. Find it and eliminate it at once.
 Story summary
Once at Twilight Town, Roxas notices Xion up at the Station Tower. Once he meets her, she tells Roxas of her failure to eliminate the Organization XIII impostor. Seeing her sadness, Roxas proposes the two work together.
 Mission walkthrough
With Xion's mission objective now added to your own, you will need to satisfy both to fill your Mission Gauge. Fortunately, the mission is set up so that you will be obtaining emblems first and facing the Avalanche after you're finished. To obtain 100% completion, be sure to collect all of the emblems while their rings are visible. Rings can be reset by defeating the Heartless along the way.
The mission starts at the Station Plaza. Before running ahead to the Underground Passage, go behind the starting point and look to the left; behind the steps is an emblem and the Ordeal Badge. Quickly grab the emblem then run towards the entrance to the Underground Passage, here is another Organization emblem. Proceed to the Underground Passage, defeating Heartless if you need to reset the emblem rings. From the entrance of the area, follow the steps downward collecting the third Organization emblem. Jump onto the ledge and prepare to fight a Poison Plant. (You need to defeat the Poison Plant before you can use the yellow switch to unlock the gate.) Jump to reach the Organization emblem then immediately Glide/Air Slide to the left, there's another Organization emblem in the air! Defeat the Poison Plant then unlock the switch on the blue gate. Turn left to obtain another Organization emblem and run straight (ignoring the entrance to the Tunnel). Follow the path to reach an Organization emblem.
Now head through the Tunnel, defeating a Gigas Shadow and claiming two more emblems. Follow the path down to obtain the final emblem. Be careful opening the treasure chest, it contains a Cymbal Monkey. Exit the Tunnel, turn left and follow the stairs up to reach the purple switch. Defeat the Gigas Shadow and flip the switch.
You now appear in the Side Street; continue straight and go Under the Tracks to obtain the Unity Badge. Head to the Sandlot to face the Avalanche. After defeating the Avalanche, the Mission Gauge fills enough for you to RTC.
Head back through the Underground Passage towards the Station Plaza. Here you will encounter two Mega-Shadows and a Neoshadow. You can defeat them for munny and HP. Whenever you're done, head over to the Dark Portal and RTC.
 Challenge Mission