The Door into Summer
After having a brief encounter with the phased-out Eureka, Renton sets with Ao to Iwato-Jima where he thanks Toshio for taking care of his family and then decides to make use of the Quartz Gun to destroy the original Scub Coral at his timeline and prevent it from spreading itself throughout the dimensions. As Ao confronts him to stop it, he learns that surprisingly, Truth has not fully disappeared, but has become the Nirvash Neo's archtype instead. Ao then decides to make use of the Gun's last shot to change Eureka's fate and have her reunited with Renton. Because of it, Ao is transported to the year 2027 where he bids farewell to Truth and returns to Iwato-Jima to resume with his life, despite the fact that there's a chance that no one in the world remembers about him anymore.
Aired 20/11/2012EP 24 - The Door into Summer

Eureka Seven AO
The story is set on Okinawa's isolated island of Iwado, which has seen a growing movement advocating a return to an autonomous government. Ao Fukai, a 12-year-old boy with a missing father, lives on the island with an old doctor named Toshio and is about to enter middle school. Ao's mother was taken away a decade ago by unknown individuals. Naru Arata, Ao's 12-year-old childhood friend and the story's heroine, lives with her father, older sister, and grandmother. She has a "Yuta" power awakened within her due to an incident when she was young. A mysterious entity called "Secret" suddenly appears and launches an attack on the Scub Coral lifeform on the island. Ao launches a certain military FP called "Nirvash" aboard a Japanese military transport in his fervent desire to protect the island.
(Source: FUNimation)