The Mission of Seemingly Harmlessness is a Kingdom Hearts parody featuring the main cast of KH1 and some from Chain of Memories. Due to it being made before Kingdom Hearts II, there are some inaccuracies involving the plot.
The movie starts off with riku and Mickey talking about controlling the dark powers in a Hallow Bastion hallway. Mickey tells Riku to meet some friends with him at a tavern. They meet Squall in the Minimalist Tavern, who is soon joined by Sora, Kairi, Donald, and Goofy. They decide they are about to embark on an adventure and then cid pops up blocking Leon out (much to his annoyance) and swearing, while insisting he come along.
They then walk along a vast space of some sort where every room looks exactly alike. Eventually they decide the group is too big to appear on screen at the same time and they split up. Leon tells his group that they are heading for a TT Plane (may be Traverse Town or Twilight Town).
Five seconds later their onboard, and looking at uneaven windows. Squall and Cid start singing "Simple and Clean" the theme song from the original Kingdom Hearts. Sora proclaims that they are "scaring him" and Cid responds that he didn't know that he was singing out loud. They are interrupted by an announcement that if they do not take all their luggage the airline staff will eat it (which Goofy finds "Threatening). Leon and Cid start thinking the lyrics to the song, and Sora says "I saw that" to which Cid gets pissed because its a cliche to have people read thought bubbles in these films.
The action then switches back to Mickey's group, as they pass through hollow bastion. Then abruptly returning to Sora trying to engafe Vexen in battle but being unable to move. Vexen proclaims he is dead and vanishes which Sora does not find to be odd. He informs the others that the Organization is there, and they respond with nonsesnse. The action switches breifly to Mickeys group where Riku askes why they aren't with the others in Twilight Town to no answer. It switches swiftly back to Leon, who proclaims "Its so uncool to the max that they left us here". They then encounter Ansem and Diz who are the same person pretending to be 2. Sora punches him in the kidneys because it seemed to him like a funny thing to do, and the group hide him in the trunk of their car for some reason
Meanwhile with Mickey, the group passes the "Hollow Bastion Gift Shop" which "has all the crap you think ya need but really don't". Riku wants to stop but Kairi makes him press on (possibly she wants to see Sora badly). Switching back to Leon's group Sora randomly proclaims "EEEEEEE I'm Sora!" to witch Cid calls him a "Potato brained ass wipe excuse for a main good guy". Mickeys group then come out of Hollow Bastion proclaiming what a good time they had because Riku paid for everything (much to his dismay). Mickey breifly mentions that they should stop in the Library because he wants to know if Ansem The Stupid returned Goofy's How To Banish The Darkness yet (a reference to the Kingdom Hearts Parody). The action switches back to Leon's where he reviels that the mission shouldn't be all that hard because all they have to do is get tickets to see Disney's Sky High at the Twilight Town Premeir. He then goes over the directions and states that Mickey's team will glide down from a mountain because they don't have a car. He also says the 6 mile trip will take an hour and a half without traffic, possibly due to the hilly terrain.
Meanwhile Riku is too scared to glide, so Mickey decides to push him, as he grabs a hang glider. The next scene is black and white footage of him hang gliding and then crashing. Now being stuck suspended upside-down, Mickey informs him he should have just used the glide ability like the rest of them. Riku's replica shows up and has a breif argument with him before he claimed "he didn't have time for this".
It then moves to show Sora driving the others, then being arrested as soon as Leon questions it and sentanced to 8 years in prison. After 45 minutes there are inexplicably released, and head towards the theater. Unfortunately their car was towed along with Ansem, so they run to the theater, with Sora screaming that they are not going to make it even as they arive, then saying "WE MADE IT!" After the movie they all hang out, and Riku and Sora wonder why Kairi is not at Destiny Islands like at the end of the game.
The Credits Roll, while Riku, Squall, and Cid sing the theme song. After the credits it shows them four weeks later as they realize they left Diz in the trunk and never got the car back, and therefore he must be dead.