Monogram and Carl inspect Agent P's many lair entrances while Candace tries to speak to the Mysterious Force.
Plot[]
Major Monogram begins a full diagnostic of every O.W.C.A. lair entrance while Doofenshmirtz is on vacation. The process accidentally deposits Perry into Monogram's lap before he's dismissed for a "Doof-free day." Carl, meanwhile, is assigned to physically crawl through all the tunnels to check each entrance and soon gets hopelessly wedged inside. As Monogram monitors the system, his voice echoes through random lair openings all over town—some of which happen to be inside the Flynn-Fletcher house. While testing the entrances, Carl gets stuck in a tunnel.
On the surface, Phineas and the gang decide to engineer the perfect Arnold Palmer. They build a massive backyard drink-mixing apparatus with industrial blenders, chemistry readouts, scorecards, and a treadmill for Buford's "quenchability" tests. Isabella evaluates flavor with an increasingly picky palate, Baljeet manages the ratios with scientific precision, and Buford becomes progressively more dehydrated and dramatic. After dozens of combinations—and rising tempers—Ferb adds a single mint leaf that finally produces a unanimously perfect beverage.
Candace, initially dismissive, grows alarmed as the project escalates. When she hears Monogram's voice coming up through the bathtub drain, she becomes convinced the elusive Mysterious Force that always removes her brothers' inventions is contacting her at last. She transforms the bathroom into a shrine and, with Stacy's reluctant help, attempts to decode what she believes are supernatural messages—actually just Monogram talking to Carl. When Monogram tells Carl he has "ten minutes," Candace interprets it as the Force revealing exactly when the invention will vanish and rushes to get her mom home in time to witness the setup intact.
Meanwhile, on the beach, Doofenshmirtz grows irritated with the inattentive cabana boy (whose name he keeps misremembering) and builds a Bring-Me-a-Drink-inator out of random vacation gear. As Candace drags her mom toward the backyard, Monogram accidentally opens a giant lair entrance beneath the kids' machine. The entire drink rig is launched across town, crashing onto Doof's inator and dispensing a perfectly-mixed drink. Witnessing this, Doof happily quenches himself with the drink.
Perry activates an emergency release to close the runaway entrance, freeing Carl in the process. Candace arrives with Linda just in time to find the backyard empty, her busting attempt foiled yet again. Linda attributes Candace's distress to the summer heat. Back in the lair, Monogram congratulates Carl before revealing there are still international entrances to inspect, prompting Carl to faint. Candace, still hearing Monogram's voice echoing through the pipes, curses the Mysterious Force while Stacy teasingly calls her by her new "Force name": Carl.
