What I think would happen if these two met. They might be able to help each other. (Not my best summary but it is good)

Lincoln and his sisters prepare for a boring five-day vacation in Danville, but as their new neighbor Isabella's backyard swimming pool is revealed to be stuck under maintenance, they decide to make their own with Phineas and Ferb. Meanwhile, Perry has to cope with the Loud family's pets as he has to stop Doofenshmirtz yet again... from growing grass everywhere.