One Step at a Time is a special mission in the next Bloons Tower Defense game. In this mission, you must survive many waves of bloons (the number of waves of bloons is equal to the number of types of bloons that are in the game). All of the waves have ten of the same type of bloons, and the waves are arranged in order from lowest-difficulty bloons to highest-difficulty bloons. You get more money than normal in this mission, and you start out with 250 lives. If you complete the mission, you get $400 Monkey Money.