The Mystery of Ferb's Bio-Bro: Secret Sibling Shenanigans.

 Plot summary:  Secret sibling shenanigans is part one of a Phineas and Ferb comic story called 'Mystery of Ferb's bio-bro' which is based on Ferb finally meeting his long lost borther after a decade. The problem is that Terrance Fletcher AKA Zacros Xalon is not exactly decent in terms of behaviour and kindness...

Plot: 

The comic begins with Ferb and Phineas finishing off their vortex surfing project, in which Phineas declares is a true success. The boys then go in for food and games. Meanwhile, Agent P goes to Doofenshmirtz, only to find that he and Mitch have formed an alliance, and they are planning to take over the entire Tri-state-area with robots.

Meanwhile, Ferb and Phineas discuss family matters and Ferb decides he must go an think. He eventually manages to remember about a brother he had when he was little, but then he just vanished and was no longer present in his life. Back at the house, Ferb, or so it seems, kidnaps Phineas and locks him away, only so he can steal his image and pretend he is Phineas himself.

Back at Mitch's ship, Perry and Meap work together to defeat Heinz and Mitch in a battle, and the villains flee. Heinz then accidentally destructs the robot army and all the plans are ruined. Perry and Meap then leave in triumph.

When the real Ferb returns home, he discovers that his biological brother, Zacros Xalon has returned somehow, and has taken over the position of Phineas, as he looks just like him. Zacros orders Ferb to build a slave ray so he can rule the world, but Ferb refuses. After a brief struggle, Zacros leaves and Ferb is left to explain why Phineas is missing.

Back at th hideout of Zacros, it is revealed there how he got disowned, from his perspective, and lived alone for his childhood, and then how he returned. He explained how his shape-shifting powers were caused by an in-ator, hinting Heinz was the origin for those abilities. Zacros then leaves Phineas to rot in his cloud prison, while Zacros, morphed into the image of Phineas, goes off to conquer the world...

Continuity: 


 * Phineas mentioned Ferb's cousins from 'My fair goalie' in a conversation at the start of the comic.


 * Meap and Mitch return from 'The chronicles of Meap' episode 38.


 * More of Ferb's British origin and past is revealed.


 * Some of the aliens from 'Out to launch' and 'The chronicles of Meap' are present.


 * This is the second time that Phineas alone has been captured, the first being the 'Transport-inators of doom game online...

The ending of this comic links in to the start of part 2, The shocking truth.