Phineas hid behind Bucky when Dad came into the house.

Bucky seemed as though he thought Phineas was hiding from him. He kept turning around to try and get Phineas to face him.

Phineas had been really happy when Mom told him Dad was coming. Dad was named Lawrence, and he was Mom's friend. Phineas and Candace had always gone places with him, like to the zoo or the park. Phineas liked Lawrence so much that he had started to pretend that he was his son and he was his dad. He even started calling Lawrence "Dad". At first Candace had told him not to, because Dad wasn't really their dad, but then she started calling him dad as well.

And now Mom and Dad were going to get married, and Dad really was going to become their dad. He was going to start living with them.

But Mom had told Phineas that Dad had a son, too, and they were both coming to live all together. And so that was why Phineas decided to hide behind Bucky.

Phineas didn't want Dad to have a son. He wanted to be the only son.

"Hello, Phin!" Dad said brightly, shutting the door behind him. He had a suitcase with him. "How are you doing today?"

Phineas hid behind Bucky even more. Maybe if he hid himself really hard, he would vanish into another dimension, like the one he read about in his storybook. Dad would worry about him. He would forget all about his real son and go on a quest to find Phineas.

Bucky was starting to get very nervous. He didn't like the fact that Phineas wasn't in sight. He whirled around. Phineas pushed him back into a sitting position.

Dad's son suddenly appeared from behind the suitcase. He peeked at Phineas through the handle.

Phineas looked back at him.

Mom came into the room. She gave Dad a hug. "I was starting to worry about you two."

"We ran into a bit of traffic." Dad said. "It's very odd. People drive on the wrong side of the road all the time."

Mom rolled her eyes. She patted Dad's son on the head and called for Candace.

Candace ran downstairs, holding her Ducky Momo doll. She looked at Phineas.

"Bucky is going to send me into another dimension." Phineas said quietly.

Bucky started to whimper and tried to turn around again. Phineas pushed him back.

"Candace, Phineas, this is Lawrence's son, Frank." Mom said. "He's moving in, too."

"They seem to be a lot alike already." Candace pointed at Phineas. "That dog doesn't make you invisible, you know."

Phineas frowned. Candace wasn't supposed to tell everyone where he was.

"Phineas, honey, come say hello." Mom said.

"Hiding." Phineas explained.

"Come on."

Phineas emerged from behind the now completely panicked Bucky and stood in front of Candace.

Frank blinked at him, but didn't say anything. He seemed to want to disappear into the suitcase. Phineas wondered if the suitcase would work better than Bucky did.

"This is Frank." Mom said gently, as if Phineas hadn't already heard the name.

Phineas frowned. Frank. He didn't really know how to say that.

"Hi, Ferb." He said nervously.

Frank looked at him.

That wasn't right. He tried again. "Hi… Ferb."

Frank smiled shyly at him. He came out a little from behind the suitcase.

"His name's not Ferb." Candace said, cuddling Ducky Momo. "Gosh, Phineas. Get it right."

"Ferb." Phineas insisted. It sounded better to him than Frank, anyway. Frank was too hard to say. Ferb was easy. Besides, Ferb looked like his name was Ferb.

Dad took Ferb's hand and led him over to Phineas and Candace. Ferb was holding a little flag in his hand.

"Is that a castle flag?" Phineas asked.

Ferb smiled and waved his flag, but he didn't answer. He came a little bit closer to them.

"Candace and I made a castle once in a sandbox." Phineas said. "It had three towers. I wanted to put on one on top, but the sand kept falling and Candace didn't want to do it anymore. One day I'll make it again and I'll make four towers and one of the towers will be tall enough so that a bird can fly to it and sit on it, and we can call it Bird Castle."

"Birds have scales." Ferb said quietly. "Like reptiles. Some people think they came from dinosaurs."

Phineas smiled. Candace was smiling, too.

"This is Bucky." Phineas said, holding up Bucky to show Ferb. He wasn't strong enough to lift the dog completely into the air, so he just held up Bucky's front half. "He's our dog. He's good. He likes food."

Ferb patted Bucky on the head. Bucky was happy to finally be able to understand where Phineas was. He barked.

"Well, I think we'd better get you two settled in." Mom said. "Ferb- I mean, Frank, you and Dad can come with me. The spare room will become your bedroom."

"No." Phineas set Bucky back down on the ground. "Ferb can live with me in my room."

Ferb smiled and nodded.

"Phineas, honey, that's very sweet, but we can't move the spare room bed into your room." Mom said. "It's too heavy."

"He can sleep on my bed." Phineas said.

"Then where are you going to sleep?" Candace said. "On the floor?"

"We can make a new bed." Phineas said.

He ran into the hallway and threw open the closet door. He knew exactly how he was going to make his new bed.

Ferb and Bucky ran after him. Phineas was glad. He was going to need the extra help.

"Okay, help me get this out." Phineas said. He pointed at a huge inflatable yellow boat. Mom always used it when she went on the lake with her friends.

Ferb helped him pull the boat out and carry it upstairs. They set it down on the other side of Phineas's room, next to his original bed.

"Needs a mattress." Ferb said softly.

"A what?" Phineas asked.

Ferb went over to Phineas's first bed and pulled back the sheets. He pointed at the mattress.

"You mean the giant pillow thing? There's one on the Spare Room bed. We can get it and put it in the boat and then get mom to put bed things on it."

Dad opened the door. "Oh, there you are. What are you lads up to?"

Phineas explained his bed idea to Dad, who was very impressed. He went down and got the mattress for Phineas, and helped him switch the sheets and pillows onto his new bed.

"Perfect." Phineas said. He climbed into his new bed and giggled. "It is a boat bed. Ferb, your new bed is cool, too. It has a shelf. I used to keep my storybooks on it, but you can put other things there if you want. I can move them."

Ferb shook his head.

"I'll get Linda to find some sheets for you." Dad went back downstairs.

Ferb pointed over at the wall at a drawing that Phineas had hung up the day before. Phineas had drawn it all by himself, and Candace had helped him hang it up.

"Do you like it?" Phineas asked.

Ferb nodded.

"It's a car." Phineas sat up on his new bed. "It's not just a normal car, though. It can fly and be a robot. When I'm big, I'm going to invent a car."

It didn't really look too much like a car, mostly just a red blob. But Phineas was sure he'd be better at drawing when he had his next birthday.

Ferb pulled a pen out of his pocket and started drawing something on the corner of the paper. Phineas marveled at this. Normally someone would have asked him if they could add to his drawing, but Ferb seemed to know somehow that Phineas wouldn't mind.

"I'm three and a half." Phineas leaned on the edge of his bed. "How old are you?"

Ferb pulled back from the drawing and pointed at what he had added.

"Little wings." Phineas said. "Metal wings, right?"

Ferb nodded.

"You don't talk that much." Phineas observed.

"I like doing things more. Besides, you don't have to talk to have people understand." Ferb said.

"You can help me." Phineas said. "When we get big, we can make the car together. Like we made my new bed."

Ferb looked thoughtfully at the car drawing. He opened the door and left the room.

Phineas was confused. Where was Ferb going? Why didn't he say where he was going?

Ferb entered the room again a moment later, dragging a huge toolbox. He opened it up and started taking tools out.

Phineas climbed down from his bed and sat down on the floor next to him. "What are you making?"

Ferb took some metal pieces out of his pocket and began to hammer them. Phineas watched him for a while as he worked.

After a while, the pieces started to look familiar. Phineas smiled. "You're making the car. A tiny car. Can you really make it fly?"

Ferb nodded. He handed Phineas a piece of metal and a tool and showed him what to do with it.

"And it should have a swimming pool in the trunk." Phineas said. "So that people can swim while they fly and drive."

Ferb nodded.

It was almost dinnertime when they finally finished. Ferb cleaned up the tools and shoved them aside.

The car was perfect. It was only a toy car, but it was perfect. Phineas gazed at it in wonder as it flew around the room.

"You can show me how to make things?" Phineas asked.

Ferb smiled at him.

"And I can tell you what to make." Phineas said. "We can make so many things, Ferb."

He gave Ferb a hug. Ferb felt stiff, though, like Bucky always did when Phineas tried to put clothes on him, so Phineas stopped hugging him.

"Sorry." He said quietly. "I just thought… since Dad is my dad too, we could be… brothers. So I thought you wouldn't care if I hugged you."

Ferb watched him carefully. Then he stood up and hugged him back.

"I always wanted a brother." He said.

"Me too." Phineas said happily.

The door opened.

"Aw." Mom said happily. She and Dad were standing in the doorway. "Look at you two. I was worried you might not get along at first."

"Mom, Ferb's staying forever, right?" Phineas said.

"Yes, yes he is." Mom said. "He's part of our family now."

The boys smiled at each other.

Candace squeezed around Mom and Dad and frowned at the flying car, which had landed innocently on Ferb's bed moments before. "What is that?"

"Our flying car we made." Phineas said. "We made it together."

"How sweet." Mom said. "Did Ferb share his toy car with you?"

"That was Phin's, wasn't it?" Dad scratched his head.

"Well, come on down for dinner, you two." Mom said. "I bet you're hungry."

Mom and Dad went downstairs. The car began to fly again.

Candace stepped back. "What the… where did you get that?"

"We made it." Phineas said. "I told you."

"You couldn't have made that." Candace said. "It's impossible."

"Nothing is impossible." Phineas said. "Come on, Ferb, let's go have dinner. Bucky likes spaghetti. You can feed him a piece if you want."

The two boys ran downstairs. Candace watched the car carefully.

They couldn't possibly have built that thing. Phineas was just being funny.

She shook her head and started downstairs.