Again another dimension
So the beginning is really the same as every other episode, it starts off with Phineas and Ferb building a contraption, this time it's a colour changer portal, walk through the portal and you come out through the next one and change colour. "Whatcha doin'?" Phineas greets Isabella, and they have a small conversation about, as always, what they're doing…
Isabella agrees to test the portal, and comes out fully pink. Then it goes to Dr. Doof who is watching television, the doorbell rings and he sets up a trap and answers the door with a piece of string, obviously expecting Perry to be there, instead in the trap he found Professor Goodensmirtz, bruises and all, after a few back stories they agree to team up.
Back to P&F and Isabella, Isabella is annoyed at Phineas as her mum is going to completely freak out when she finds out that she is pink, they tell her not to worry because she only needs to step through the portal again, but as she does Dr. Doof's Inator that allows him to travel to the 2nd dimension accidentally fires on the portal and Isabella is sent through, P&F jump through after her, shortly followed by Candace who screams as she jumps in.
They find themselves back in the 2nd dimension, at Doof's House, 2nd Dimension Doof is there and playing with his train and Phineas talks to him like an old friend and tells Isabella about last time, he suddenly remembers about Agent P and everything else. "Whoa, sudden headache!"
As he remembers, Doof and Good from the 2nd dimension use a successful Inator, Phineas picks up a pamphlet and opens it up, "So you've discovered your pet is a- Ferb, look!" Ferb turns round and Phineas falls through a portal in the book, he is clinging on to the pages of the book but they start to tear, Phineas lets go and falls into the pit of lava below him, well he would've if Isabella hadn't have grabbed his hand and pulled him back up, he suddenly remembers, "Uh! I remember, Isabella!" He kisses her slowly and softly, they come apart, and Phineas declares they are going home.
They get back home, and lay out under the stars together.
Thanks guys, I'll be posting the dialogue after I've uploaded this.