Mission 00 in Kingdom Hearts 358/2 Days is a tutorial mission, which introduces basic elements of Mission Mode, such as Gathering Gates, Mission Points, and Mission Mode RTC. This is the only mission that is not playable in Story Mode. This mission must also be completed in order for the rest of the missions in Mission Mode to appear.
Defeat five Scarlet Tangos.
Exit the Under the Tracks area and head north on Side Street to reach Station Heights. Once there, proceed up the hill, defeating Shadows, smashing crates, and picking up blue crystals to obtain Mission Points. Once at Station Plaza, the targets will appear two at a time. Perform aerial combos and cast Blizzard magic to defeat the Scarlet Tangos. Avoid their fire attacks at all costs.
When the last Scarlet Tango is destroyed, a countdown appears on-screen. You have 120 seconds to return to the dark corridor. Normally, failure to return in the allotted time results in the loss of bonus Mission Points. In order to obtain a Crown, you must return to Under the Tracks in time to receive bonus Mission Points. Simply step on the dark corridor to complete the mission. It is possible to turn the 120 seconds off from the menu screen.