Now that Paper Mario has joined the bros, they can reach new places. Near the tri-color block is a narrow crack. Press (Y) near it and Paper Mario will turn sideways to slip through the crack. Jump up the nearby hill and you'll find a Goomba carrying off a Paper Toad. Apparently, the Paper Toads are about to do some real work for a change. The bros approach and the Goomba leaves. Battle the level 3 Paper Paratroopas.
Take the southwest exit and you'll find some Biddybuds that will stack. There are coins, a Refreshing Herb, and a 1-up Mushroom in the item blocks. Return and take the northwest exit. There are more Paper Toads being carried off by Goombas. Battle them and defeat the Goombas in battle to free them. (Regardless of what enemies appear during the battle, defeating the Goombas will release the Paper Toads.) There are eight that need rescuing here. Walk to the left and Paper Mario will show off that he can flip sideways to pass throw narrow spaces. Talk to the Paper Toad to get him to come along.
Go west. At the top of the hill is a Paper Toad bouncing on Music Note Blocks. Time your jump to hit a block to knock him off. He went crazy because there aren't many 3D blocks where he's from. There's another Goomba with a Paper Toad on the hill. Walk to the south and you'll find a blue Paper Toad who's super fast. Walk near the water to find a fence made of Paper Toads. Talk to them and explain the speedy Paper Toad to get the Dash Socks. To use them, start moving and press and hold (X) to jump. Release (X) when you land to begin dashing. Run through the flowers for coins. To slide to catch someone, dash, then press (A), (B), or (Y) when the exclamation point appears. You'll use it to get the other two Paper Toads, and the speedy blue Paper Toad. Lakitu appears, saying he took the Paper Toads to Peach's Castle.
Head as far east as you can go. You can get the first strike on enemies by dashing. When you reach where you first met Paper Mario, someone has a delivery for the bros. It's a Toad with an item and letter. A Paper Toad wants to thank the bros for saving his friends. The item is something the bros can use in battle. The more Paper Toads the bros save, the more battle items the Paper Toads will make. Someone says they have orders to hunt down and destroy the bros. It's a small army of Goombas. In battle, Paper Mario has the Trio Attack command now. This allows Paper Mario to use Trio Attacks, which also consume BP. The item is a giant cardboard hammer all three bros swing at enemies to turn them into paper. The first one is Trio Racquet, where the bros play racquet ball, using enemies as targets. All three bros must be able to move to use a Trio Attack.
While you're in the area, dash to the orange spring platform to be launched across the water. Go east and you'll find that parts of the environment are made of paper. Paper Mario says this is what his world looks like. Luigi doesn't think that they came from the book, pointing to some cardboard with Bowser's face on it. Dash into the spring to launch through the cardboard. Go east and a Toad says they need the bros' help. Bowser is invading Peach's Castle. Well, it was bound to happen sooner or later... Of course, there are two of them.
Meanwhile, in Peach's Castle, Peach hopes the bros are all right. Paper Peach thinks they should have run into Paper Mario at this point. Bowser laughs. Peach guesses it's that point in the story. Paper Bowser flies in on his clown copter. He wants both princesses, but how he's going to transport Peach is anyone's guess. Bowser flies in on his clown copter. The Toads panic, as per protocol and run off. Bowser asks Paper Bowser if he's trying to steal his thunder. They're still not getting along all that well. In the background, there are suddenly two paper princesses. One asks Mario to save her. Paper Bowser notes she sounds different. Bowser says it's kidnapping time. They both say nothing gets in the way of that and breath fire on the paper princesses. They chase the princesses into the throne room. The Bowsers surround them. The princesses try to leave the throne room, but Peach trips and falls. She calls for Mario
Starlow says they should return to the castle immediately. She thinks there may be time but Bowser disagrees. Both of them have their respective princess in their respective clown copter. Bowser introduces Paper Bowser to them. They found common ground in taking Mario down. They also found teaming up make kidnapping the princesses easier. They then squabble about kidnapping technique. Paper Bowser says their headed for his castle and that the bros will try to follow them, as per usual. Bowser gives them something to keep them busy.
It's Petey Piranha. He can pick up a bro and chomp on them, keeping them from battle for a while. Trio Attacks work on bosses. He'll jump to unleash a shockwave on the bros. Time your jumps to dodge. The Fire Flower attack does critical damage, so use it often. After a few attacks, Petey Piranha will get mad and chase the bros. Paper Mario will turn into an airplane. Move the airplane over the bro being attacked and have them jump to hold on. Hold the button until they land on the ground. Press (Y) as Paper Mario lands on Petey Piranha. If one of his attempts to grab a bro fails, he'll fall backwards. He'll take more damage this way.
Once defeated, a ? Card appears. A Toad can't believe one was found here. They can be used with Amiibo to create character cards. If you don't have Amiibo, you can sell the cards.