There are 9 chapters and each has a few maps for a total of 15
Chapter 1 map 01
Chapter 2 map 02
Chapter 3 map 03
Chapter 4 map 04
Chapter 5 map 05
Chapter 5 map 06
Chapter 5 map 07
Chapter 6 map 08
Chapter 6 map 09
Chapter 7 map 10
Chapter 7 map 11
Chapter 8 map 12
Chapter 8 map 13
Chapter 9 map 14
Chapter 9 map 15
Android 21 (final boss) is at Level 35, EVERY map can be played in a few or all of the available matches by following the least or the longest route depending on your preference (doesn't matter) as long as you fight the purple boss battle to progress.
This is simple if you have a character level 35 - 100
- you can buy them in the Lobby to your right (of story selection) there is a shop they sell characters for 1,000,000 Zeni or 1,000 Premium Z coins its in the 2nd tab titled STORY.
currently they gave the community 2 million Zeni and Ive already accumulated 500,000 doing rank, player & arena matches along with story. its not hard to accumulate 1million but its abit of a grind but the level 100 characters make this achievement and other story achievements fast.