Naruto, which episode is about the fourth generation seal Kyubi no Youko?

The first episode. A little bit. The episode that introduced their relationship was 388, which was said by four generations themselves. ....

Naruto's father is the fourth generation of Naruto. Naruto's original name was Namikaze Minato, and his mother was Uzumaki Kushina. Naruto's parents died because they wanted to seal Kyubi no Youko in Naruto's body. At that time, Uzumaki Kushina, Naruto's mother, told Naruto that the drama series was .466 ~ 468.

You can learn more details directly from Baidu Encyclopedia Namikaze Minato.