This is the story for SSBA.
It shows Peashooter and other plants fighting off hoards of zombies. A zombie is almost about to eat Peashooter, but then Frank West comes in riding with Blue Light Special and kills the zombie. Then, you have the choice to either play as Peashooter or Frank West. When you choose, you have to fight off a hoarde of 30 Zombies. When you defeat these, Doctor Zomboss appears, and you have to fight him. When you do, his machine falls to the ground. Then Peashooter and West turn around and start walking away, but Dr Zomboss pulls out A Dark Cannon and shoots West with it. Then Dr Zomboss grabs his trophy, and flies away in a machine. Peashooter tries to shoot him down, but fails. Peashooter then chases after Zomboss into Slender's Forest and the chapter ends.
Octodad and his family are in a car, and Scarlet says "I can't wait for camping, can't you kids?" and Stacy and Tommy agree. Then Octodad stops the car, as they have arrived at thier camping spot, which turns out to be Slender's Forest. You play the level, and then another cutscene appears, of Octodad and his family are sitting around a campfire. Then Peashooter comes in, still chasing Dr. Zomboss. Peashooter shoots him, and Dr Zomboss drops Frank West's trophy, and teleoprts away using a machine. Peashooter revives Frank, and then sees Octodad and his family. Then, Slenderman appears, and you have to choose who fights him. After that fight, Slender turns into a trophy, and Octodad carefully revives him. Slenderman immediatley jumps back, and his tentacles come out, holding a dark cannon. He fires at Frank West, but Frank uses Clearing Up The Mess, to throw it to the ground. Slenderman, out of anger grabs Octodad's family and teleports away. The chapter ends.
Doctor Zomboss is seen teleporting into a room with a figure named the The Animacion. Seeing that Zomboss hasn't returned with any trophies, he is angry with Zomboss. But, Slenderman teleports in with Octodad's family, and The Animacion smiles.
This chapter isn't finished.