Isabella is in the hospital with a tonsil infection. Phineas and Ferb decided to go visit her. The doctor did Isabella's daily check-up and left the room. Just then, Phineas and Ferb walked into the room. "Hey Phineas!" said Isabella in a soothing, but harsh tone. Phineas replied, "Hi Isabella, Whatcha doing?" Isabella pointed to her mouth. "Yeah, I get that" Phineas replied. "But what new news do you have about your infection?" "Oh, hey Ferb! Yeah, they removed my tonsils and they said I can leave this afternoon!" said Isabella. "Nice, you know that now you can have as much ice cream as you want now that you removed your tonsils," said Phineas. "Oh, my goodness, yes, I would love too!" replied Isabella. "Ferb, I know what we're doing today," exclaimed Phineas. "Ferb, I need you to make a plan. Actually, we don't have enough time. Go to blueprint heaven and get some blueprints for a giant Sundae machine, I'll call blowtorch city and go home to meet the delivery guy." said Phineas.
Meanwhile, at Vanessa's house…. "Ok, honey, I'm going for cooking class. Remember, you're at your dad's this weekend," said Vanessa's mom. "Great another weekend of evil." Replied Vanessa. "Vanessa Doofenshmirtz, your father is not evil. We just wanted different things and never got along." "Mom, HE IS EVIL! And I'm going to prove it to you. See he even has his own evil jingle right on his answering machine." Replied Vanessa. Vanessa rang his dad's phone expecting the answering machine but then… "Hello…" said Doofenshmirtz. "Oh, hello Heinz-." "Dad! Why'd you pick up, you always let the machine answer!" interrupted Vanessa. "I know, but I was near the phone so… oh and by the way, could you pick up some blueprints for me on your way over, sweetie, thanks!" "Great, now dad wants me to get blueprints for his evil 'inator' contraption." Said Vanessa sarcastically. "And when he is done then I can prove it!"
At blueprint heaven, Ferb was busy getting the blueprints. "So, you wanna blueprint for a huge Sundae machine. Well, I don't think we have any but lemme check. Oh, you're lucky I found one." Said Carla, the shopkeeper. Just then Vanessa walked into the store. "I'm here to pick up an order for Dr. Heinz Doofenshmirtz." Said Vanessa. "Oh yeah, baby, your daddy just called." Said Carla. Vanessa went home and gave Doofenshmirtz the plans. "So, uh, dad… This thing you are building, it's evil right?" asked Vanessa. "Yes, Yes, it is. Glad to see you take interest in the family heritage" exclaimed Doofenshmirtz. Doofenshmirtz finishes building his inator and Vanessa gets curious. "So that thing must be really evil, huh…" Vanessa sarcastically exclaims. "Vanessa, take a look outside and tell me what you see" asked Doofenshmirtz. "Umm, not much." "Exactly… ever since the stupid billboard came up, it blocked my view of seeing all the misery of the people of Danville. But now, I will turn the whole tristate area into the twisted image of Dr. Heinz Doofenshmirtz!" (evil cackle) said Doofenshmirtz. Vanessa becomes very confused. "Wait, since when are a doctor." "You know, they don't give these out to anyone" (Heinz holding up his doctorate). Vanessa holding the price tag says, "anyone with 15 bucks?" "Ok, that's enough looking." Reported Doofenshmirtz. Perry gives out a small chuckle from the trap. Doofenshmirtz holds the button and cackles "Now, to unleash my reign of terror…." Perry suddenly throws his blade at the escape button and jumps out of his trap. He then kicks the space laser inator to face the wrong way.
Just then, Phineas and Ferb made the Sundae machine and the started the machine. It made a perfect Sundae and Candace got home with Mom (Linda) at the right time. The space laser inator just in time, instead of shooting the billboard, shot the Sundae machine and the Sundae machine vanished into thin air. Just then, Linda walks into the backyard and sees the boys standing with a huge Sundae. "Hi mom, we made a huge handmade Sundae for Isabella," said Phineas. "Aww... That's so sweet. C'mon, I'll help you drop it off at her house. Candace stands there still, so embarrassed. Meanwhile, Vanessa also planning to bust her father brings her mom to the so-called "evil lair". There, she sees Doofenshmirtz sitting on the ground with a platypus. "This is not evil! Aww… Heinz, when did you get a pet." Exclaimed Vanessa's mom. "Mom, it's not his pet, it's a secret agent!" "Secret agent?!, Vanessa, it is a platypus, they don't do much you know." Said Vanessa's mom. And yet again, Vanessa and Candace could not bust anyone whether it be brothers or father.