Kingdom Hearts 358/2 days is about Orginization 13s keyblade weilder Roxas and his time in the Organization. Roxas is a nobody but unlike other nobodies he doesn't remember his past or his true name. His first 7 days he doesn't talk to anyone but Axel Org. member 8 is the only one who makes an effort to be his friend. Roxas and Axel start doing missions together as Axel is his mentor and they become fast friends. Their routine after work is sitting on the clocktower in Twilight Town enjoying seasalt ice cream and enjoying the sunset.
Then Organization member 14 joins named Xion and she also wields the keyblade. While Axel goes off to Castle Oblivion (Chain of Memories) Roxas befriends Xion and than they start to enjoy ice cream on the clocktower. When Axel returns it becomes the 3 friends enjoying their free time with ice cream and the sunset. Xion encounters Riku on a mission and he explains her fate to her. She is a puppet made by Org. member Vexen to steal the keyblades power so they could destroy Roxas and use the keyblades power to finish Kingdom Hearts.
Xion looked like Kiari because she was the most precious memory in Sora's heart and she was Sora's memory of Kiari. While Sora was fast asleep getting his chain of memories pieced back together by Namine Xion had to make up her mind on weather to go back to him or stay with her friends. She ran from the Organization so she wouldn't have to use her Keyblade and keep draining Roxas's power. Axel was sent to hunt her down and bring her back. Roxas couldn't stand to see his two best friends fight and decided to leave the organization as well to find out why he was chosen to wield the Keyblade.
It ends exactly where KH2 begins and I really enjoyed the story. The graphics were great on the DS but it was a bit different than the other KH games. Like COM you couldn't just run around fighting heartless like in the other 2 you had to go on missions every day and fighting certain heartless. Sometimes you went solo and other times other members joined you. It was a really great game and if others have it you can play multiplayer in mission mode.