Mission 21: Collect hearts

Mission 21 for Kingdom Hearts 358/2 Days sends Roxas and Axel on a mission that ends up introducing them to a new foe.

Regular Mission
Collect hearts.

Optional Objective
Collect more hearts.

Story Summary
Roxas continues having flashbacks to the boy in red as he and Axel go on their mission to Agrabah. There, they find Pete searching for a way to the Cave of Wonders and its magic lamp.

Mission Walkthrough
This mission is long and slightly difficult compared to the earlier missions. Make sure your panels are stocked before you embark on this mission. Fire magic will be quite helpful during this mission.

Entering at the Palace, grab the chests and badge, and head down into the Agrabah Streets area. Here, you will come across a familiar face if you've played Kingdom Hearts II.It's our old pal, Pete! Pete is searching for something, and to discover what, you'll have to tail him. Basically, you have to keep him within your blue-colored range of site while staying out of his red-colored vision. If you enter the red, you start the round over. You can look away very briefly, but too long will leave you starting over like when he spots you. Stay close and behind him as much as possible and watch his movements carefully. You will do this twice, once in Agrabah Streets, and again at the Agrabah Gate. You'll be rewarded with the door to a new area.

Snag the loot at the Cave of Wonders and then hop in the head to enter. The Entrance Hall requires some rearranging to access what you'll need. First, eliminate the Heartless you can, then head for the crate in the northeast. Move it down to the southeastern corner by hitting it, aiming it for the short pillar on the end of the platform. Use the crate to hop on the pillar, and then on the platform to reach the switch. Then, hop back down and hit both the crate and the golden pillar over to the northwest corner to arrange a way up to the platform there. Destroy the Heartless at the top, then head through the door.

In the Pillar Room, get rid of the minor Heartless and you will get a nice big new one to battle: the Large Armor. This is where that Fire magic comes in handy. Good thing you have Axel with you! Once the Heartless is gone, the mission will be considered complete. You can head back at this point, or continue by pressing the switch in the northwest corner to operate the pillars. Hop up the moving pillars and stationary pkatforms to the door set high in the northeast corner. Continue through and enter the Abyss.

There's not much to do in the Abyss, other than set off the switch, which does nothing at this point, and grab the chest. When you are satisfied, jump off the ledge into the abyss. This will take you back to the Entrance Hall, but you are now on a set of high ledges. There are chests and more Heartless to defeat up here. Doing this will give you your final breakthrough. Jump back down and head out when you're done.

While you're heading back to RTC, make sure you stop in Agrabah and pick up any chests you might have missed while you were pursuing Pete. There will be minor Heartless on your way back through, but they are Pureblooded and will not add to your heart total.

Challenge Mission
Although the time limit to acquire three Challenge Sigils seems very easy, the complex mechanics of following Pete, moving the blocks around the Cave/Entrance Hall area and jumping between oscillation platforms really slow down Roxas if he is ill-equipped. The blocks and moving platforms are easier to deal with when a High Jump panel is equipped with two High Jump LV+(L) links attached. This way, you can skip moving the crate next to the tall block and also jump on high platforms before they descend all the way down.

Video
Video walkthrough here.