Damit sich Candace nicht daran erinnern kann, wie Jeremys Geschenk aussah, tut sich die junge Truppe zusammen und hüpft mittels der Gedanken Maschine in Candace Unterbewusstsein. Allerdings müssen sie sich vor ihrem schrecklichen "Es" Monster in Acht nehmen.
After losing a gift that Jeremy made for her, Candace is determined to recreate it before Jeremy realizes it’s missing. Unfortunately, Candace can’t remember what it looks like, so she enlists Phineas and Ferb to use their mind machine to enter into her subconscious and recapture the memory. Meanwhile, Doofenshmirtz’s evil plan is to use his Underwear-Inator to take over the Tri-State Area, since everyone's greatest fear is being caught in public in their underwear.
For å hjelpe Candace å huske hvordan det Jeremy har mistet ser ut, drar Phineas, Ferb, Candace og gjengen inn i Candaces underbevissthet ved hjelp av en minnemaskin, men de må passe seg for den skremmende Id.
Phinéas et Ferb construisent une machine pour aller dans l’inconscient de Candice...
