Act III, sc. 1

Luigi went to the Boneyard to water the plant that he and Pikachu had encountered earlier, and a large flower bloomed. Then they went to the back of the mansion, and the key of clubs unlocked the door to the Courtyard. Luigi attacked the Mimikyu that fell from the trees, and the chest that appeared revealed lots of money. Luigi released Noctowl and Decidueye, and they flew to a small straw building.
Inside it, Luigi saw Princess Rosalina. Like the others she was crying, but she cheered up when she saw Luigi. She explained that Mario had dropped five items around the mansion and Ash four. Pikachu shook a nearby tree and found Mario's letter. "I wonder what it says," Pikachu thought.
But they couldn't think much more as Noctowl and Decidueye flew near the creepy stone well, and Luigi and Pikachu went down it. In the room adjacent to it, they saw a Boo and two paintings: one of Mario and, to the viewer's right, another of Ash. "GET US OUTTA HEEERREEE!!!" yelled Mario from his "canvas." Luigi was too mortified for words.
In the well, there appeared a Mimikyu, which Luigi caught, and then a key to the Rec Room. In this room another Dusclops, though at its normal 68 lbs. as opposed to the 136 lbs. of the previous, was working out. Pikachu went to the western treadmill and found a key – like they hadn't found enough – and Luigi encountered a blue Gastly by the fitness machine. Luigi caught it and then took care of the Dusclops by knocking it out with the three punching bags. Somehow, they got him, as well as the Iron Medal and the room's Boo, in a snap.
The key they got went back to the hallway, which made things easier since they would go back and forth to Madame Mismagius in the Fortune-Teller's Room. They showed the letter to her, and she stated that it read "Beware of Boos!" With little more to give her, they could only find more items for her. The duo went upstairs to another door that was ablaze, and once they extinguished it, they found themselves in the Tea Room, where various Sinistea tried attacking them. Two white Misdreavus popped up, but they caught them easily. A small white chest appeared, revealing the Snow Medal, yet another projectile Luigi could use for the mansion. Luigi used the ice to slow down the Boo in the room, and they sought more items.
"I need to wash my paws," said Pikachu, so they went into the Washroom, where Luigi found a Fire Gastly (Ghost/Fire) in the latrine. After exposing its heart Luigi extinguished it for good with the water from the sink. The chest that appeared was, as usual for its color, full of money, and they got some fire for their next stop, the Astral Hall.
Inside the Astral Hall, Luigi wanted to go to the next room; but every time he went through the eastern door, he just wound up back in the room. Pikachu saw five sets of candles, so Luigi lit each. After he had done so, however, they were extinguished and the door was locked. It wasn't hard for them to catch the four Duskull, two Gastly and Misdreavus that appeared, and they easily caught the Boo as well. Before they left, however, they grabbed from the turquoise chest that appeared the Sky Medal.
Next to the Astral Hall was the Observatory. Luigi observed space through the telescope in the room, and his eye caught the moon. Suddenly outer space appeared before them, as did several shooting stars, which Luigi eventually propelled at the moon. It revealed a small five-pointed star and a PokéBall. They went up and grabbed them. "My, what glittering beauties!" said Pikachu.
They went back to the Fortune-Teller's Room to see what Madame Mismagius had to say. "When Boos gather in large numbers," she said, "their power grows stronger! All they fear is the Poltergust 6000P."
"How much is left?" asked Pikachu.
"Two items for Mario," replied Madame Mismagius, "and two for Satoshi. You will find one for each in two different rooms."
The pair stocked up on some ice at the Tea Room and went into a large room, the Sewing Room, where an elderly Banette in a rocking chair was knitting. Pikachu found a blue Gastly in a corner of the room, and after Luigi caught it, he went after the Banette by smacking her with the balls of yarn. After they got her there was a chest with a key as well as a Boo, so they took care of it and then got the key.
They went to the Bathroom across the hall, where Luigi saw a beautiful woman's silhouette. When Drifblim opened the shower curtain, she revealed a female Jellicent, and Luigi froze the water she was in, allowing him to capture her. Another chest with a key appeared.
The key from the Bathroom led to one of only two rooms that Luigi had not visited on the first floor. One was the Billiards Room, where a Golett weighing only 100 lbs. – less than half of what a normal Golett would weigh – was shooting several billiard balls.
"I could never play that game," said Pikachu sadly. "Every time I did, I ended up ripping the table just like Peter Sellers did." Luigi went to a chair in the southeast corner of the room, where a blue Gastly was waiting. After that he took care of it and then caught the Golett after smacking it with the billiard balls. The chest revealed the last of the eleven medals, the Serpent Medal, and Luigi's elemental collection was complete. (Author's note: I am not using any of the types in the Pokémon games that deal "altered" damage ["super-effective," "not very effective," "no effect"] to Ghost-type Pokémon, nor am I using those types who suffer "altered" damage from Ghost-type attacks.)
The duo went to the adjacent Projection Room, where there sat a film projector. When Luigi touched it, he could see the silhouettes of Misdreavus that, when exposed, were a reddish hue. Like the Mirror Room, Luigi and Pikachu were more interested in getting what they came for than they were in getting hugged and choked to death. The seven Misdreavus felt the cold of the Poltergust 6000P, and they were soon defeated. In the chest that appeared they found Mario's glove and Ash's belt. "Eew," said a disgusted Pikachu. "They're a little sweaty."
Before they went to the Fortune-Teller's Room, Luigi caught the two Boos he missed. Inside the Fortune-Teller's Room, Madame Mismagius could see the figure of what she called King Boo. "I need but little more," she said. "My spirit ebbs away…"
The key in the Sewing Room led to the one room that Luigi had not cleared with his first three Portrait Pokémon – the Twins' Room. Luigi went to the bunk bed and found a blue Gastly, which he caught very easily since it was practically stuck in there. Then he spun a small airplane-and-automobile mobile, revealing twin Shuppet that wanted to play hide-and-seek.
As soon as our heroes left the room, the twins were ready. Luigi could only identify who was in a box if he used the Poltergust 6000P, and if it shook, he knew that one of them was in there. He found both by doing this, and he caught both easily. After catching the room's Boo, Luigi saw a red chest in the room, revealing Mario and Ash's shoes. "They smell… like their feet," said a nauseated Pikachu.
With their items complete, Luigi and Pikachu went back to the Fortune-Teller's Room to give Madame Mismagius the last of the items. She could see Bowser in the center, fearing that King Boo had somehow revived him. Relieved to have her powers foretold, Luigi caught her easily. Another key appeared, this time from the small treasure chest, and they found the last Boo on the first floor.