Disclaimer; I own nothing.
Chapter 1 preparing the call
As Ferb lowered his harmonica he told his brother a problem.
"Phineas we need all this," he gestured towards the assembled inventions, "but we need to strike fast! We don't have time to retrofit this stuff with auto pilot systems!"
Phineas froze, and thought to himself in a panic, Ferb was right even with all the gadgets from the summer they did not have time. "Do you have a better idea." He asked his stepbrother.
"Actually yes." The green haired brit replied, putting his hand on the control panel he had been looking at. "Perry's lair has an ANB override transmitter."
"An AN-what?" Phineas asked, confused.
"An ANB override transmitter, an all networks bulletin. It allows you to send a message to the people within a set area on any television and radio that is active. If I know responsible families the parents will have gone to try and find a safe escape route but told their children to wait behind for safety. And those kids will be on the radio/ TV channels, trying to find out everything they can about the situation. Using this I can broadcast a message to the kids of Danville and call them to the backyard. Then we drop them down here through that trap door." He pointed to the backyard sized trap door. "You make sure they have a nice soft landing and then we recruit them and assign them, then we use Agent P's gadgets to find him, probably with the rest of the O.W.A.C.A agents."
"Good plan Ferb! You prepare a transmission I will use the auto-scan replication device to create a huge soft heap for the troops." Phineas yelled, excitedly. The 2 boys set to work with one goal, saving Danville.
Yeah it is short but it is to set the scene for this two shot thought there will be an epilogue that will extend to a fully blown story. And wow, I got inspiration and at least 1 (maybe 2) chapters for a fanfic in one episode.