Title: FLCLimax
Original air date: August 13, 2003

Summary:
Haruko and Canti have disappeared and become wanted criminals, while smoke has continued to pour out of the Medical Meccanica plant, shrouding Mabase in mist. Mamimi finds a small dog-like robot by the river. It runs away with her cell phone, which she lets it eat, and it grows as a result. Haruko returns to the Nandaba residence at dinner, causing Naota to later ask her in tears why she left. Commander Amarao and Lieutenant Kitsurubami attempt to find the "terminal core" of a robot they haul out of the river, which is revealed to be the device Mamimi has been feeding. It absorbs part of Canti before Haruko feeds Naota to it, then drills into the giant hand. From this, Haruko hopes to extract Atomsk, the celestial being whose power she desires. Before the giant hand can fully grasp the Medical Meccanica plant, Canti stops it as Naota emerges from his head, glowing with the infinite energy of Atomsk. Stunned, Haruko flies into a rage, bent on acquiring the power of Atomsk by destroying Naota. Before he can finish Haruko off, Naota stops short and declaring his love for her, kisses her, allowing Atomsk to fully emerge from his N.O. channel. Atomsk consumes the terminal core and blasts into space. Haruko zooms away towards the sky on her Vespa, leaving Naota to find her guitar lying amongst the rubble. In the epilogue, life returns to normal in Mabase. At the end of the credits, Haruko is seen riding off in space on her Vespa.
http://en.wikipedia.org/wiki/List_of_FLCL_episodes