The untitled Phineas and Ferb/Milo Murphy's Law crossover is an upcoming episode and the season two premiere of Milo Murphy's Law. It will premiere sometime in April 2018, serving as the one-hour season two premiere event.
Milo and his friends meet the gang from Phineas & Ferb to help them make a new time machine to stop Derek and his pistachions from taking over the world.
For a full transcript of "Phineas and Ferb Crossover", click here.
The image gallery for Phineas and Ferb Crossover may be viewed here.