"Behold! The sun setting there is me. The sun which will rise again tomorrow... is you!"
- ―Ultraseven speaking to Leo
Terror of the Saucer Race Series - Goodbye Leo! Journey to the Sun (恐怖の円盤生物シリーズ！さようならレオ！太陽への出発（たびだち) Kyōfu no enban seibutsu shirīzu! Sayōnara Reo! Taiyō e no tabidachi) is the 51st and final episode of Ultraman Leo. It is the twelfth and last episode of the Terror of the Saucer Race Series (恐怖の円盤生物シリーズ Kyōfu no enban seibutsu shirīzu) story arc.
The most powerful saucer beast is summoned from Black Star. What will be the fate of Leo, and the fate of Earth?
Black End departs from Black Star towards Earth. Meanwhile, the Miyama's go to visit the grave of the man of the family. Toru quietly mourns Momoko and Kaoru when an earthquake strikes. The incident is forgotten when Toru asks Gen to take him to the beach because Momoko would take him and Kaoru there.
They are interrupted on their trip when another earthquake strikes, and Black End rises from the ground. It calls Leo's name as it looks around. Gen tells Toru to run, and the boy refuses, believing Leo will always come to save him. Conflicted, Gen does not transform, and Black Directive calls the monster back.
Izumi continues to suspect the saucer beasts are after Leo. Ayumi and Sakiko defend him. That night, Gen wonders if he should leave Earth. Seven appears to Gen's dream and tells him that he must decide whether or not to live alongside the humans. Seven tells Leo that to win, he needs to tell the humans he is an alien.
Toru and Gen train, but Toru falls behind. Gen tells him to go to the beach to be strong in a place by himself. They do not notice Black Directive sneaking up behind them. Black End rises from the ground.
Seeing the saucer monster, Ayumi wonders whether Gen and Toru are OK. She gets the other students and they go to search for them. Meanwhile, the monster pursues the two. Gen reveals his identity to Toru, and transforms.
While Leo is battling Black End, Black Directive sees Toru on the ground and captures him, holding a knife to his throat. Distracted, Leo is beaten down and his Color Timer start to blinking and he gets flashbacks and also hears Seven encouraging him to fight.
Meanwhile, Ayumi leads her band of children to where Black Directive is holding Toru captive. They attack him, lead by her. She bites his hand and Toru grabs the ball, and throws it to Leo. Black Directive collapses.
Leo throws the ball into Black End and it dies. The children back off in horror as Black Directive melts in front of them. Black Star appears in the sky hurtling towards Earth and Leo destroys it.
Later, Gen bids farewell to the children, Toru, and the Miyamas. Sakiko tells him that if he was an alien, they wouldn't care because they all love him. Gen takes his Leo Ring off his hands says that he want to feel the Earth by himself before he says goodbye to them and leaves. Toru runs after him and waves goodbye as the Ultra sails off into the sunset, hoping to see all of Earth as a human.
- Ryu Manatsu: Gen Ohtori/Ultraman Leo (voice)
- Toru Umeda: Tsunehiro Arai
- Kenji Nakagawa: Ultraseven (voice)
- Ultraman Leo Volume 13 features episodes 49-51.
- This episode marks the last apperance of Tsunehiro Arai on the Ultraman Series and also the last time he respises his role as Toru Umeda.
- The same ball prop is used for Black Directive's crystal before and after Toru throws it to Leo, making it appear as if it suddenly grew immensely offscreen.