You were new in the city. You saw a person that you who looked like Marie. When you got closer to them, they rush away, and you chased them. That is how you got into the Squidbeck Splatoon. You where at Octo Canyon, doing some missions until you saw 2 agents, the ones who stopped DJ Octavio and almost died. They waved at you.

Agent Orange: Oh hey! You must be the one who got recruited. I'm Agent Orange.

Agent Blue: They look weak. I'm Agent Blue.

Agent Orange: Don't say that Winter!