Fathers (迫る天下一武道会 Semaru Tenkaichi Budōkai, lit. "World Martial Arts Association Approaches") is the four hundred twenty-ninth chapter of the Dragon Ball manga.
In the Capsule Corporation Gravity Room, Vegeta is in all out training mode. Trunks is also in the room, but he's straining under the heavy gravity. Vegeta tells him to leave, but Trunks says that Goten called and said he's entering the World Martial Arts Tournament, so Trunks wants to get ready for it too. Trunks then goes Super Saiyan and then starts jumping and running around with ease, much to Vegeta's surprise.
Vegeta asks can Goten go Super Saiyan as well, and Trunks confirms this. Vegeta then challenges Trunks to try and hit him, saying if Trunks can land one blow on his face, he'll take Trunks to the amusement park. Trunks immediately takes Vegeta up on that challenge and goes at him, throwing punches with amazing speed. Vegeta manages to keep his guard up for a while, but one of Trunks' punches gets through and strikes his face. Vegeta immediately punches back, sending Trunks flying.
Vegeta realizes he may have hit Trunks a bit too hard, but says he never said he wouldn't hit back. Nevertheless, he intends to keep his promise, but first asks Trunks who's the stronger of him and Goten. Trunks says he's a little stronger, because he has an age advantage and Goten hasn't learned to fly yet. Vegeta is taken aback at just how strong the next generation is becoming.
Meanwhile, Videl is shown to be getting really good at ki control, as she's now floating a good ways above the ground. Goten, however, is still flying freely, and Videl wonders when she'll get that good. Gohan answers he doesn't know, so Videl says she'll come every day until she can. Gohan then suggests to Goten that he rein it in while Videl's around.
Videl then take a break, telling Gohan not to say anything to her father about her learning to fly, because she wants it to be a surprise. She also doesn't want her father to know that she's going to a boy's house, since he won't let her go out with anybody weaker than him. But since he's the World Champion, everybody's weaker than him. Gohan asks if she's ever practiced with her father, and she says no. Gohan grins, knowing Videl doesn't realize she's a lot stronger than Hercule.
Gohan changes the subject, asking if Videl would be disappointed if her father lost. Videl just laughs, saying she'd be glad to see someone knock her father down a peg, to Gohan's delight. Videl then asks who taught Gohan his talents. Gohan answers that it was his father, before he died. Videl asks if his father was strong, and Gohan confirms this. Goten then blurts out that their father is coming back for the tournament, despite Gohan just saying he died. Videl takes it that their father actually divorced their mother, and secretly told them he was coming back for the tournament, but not her. Videl then shrugs the whole thing off and they get back to training.
Ten days later, Videl has developed her flight skills to the point of being able to fly freely, putting an end to her training with Gohan. This allows Gohan and Goten to get serious about their own training to get ready for the upcoming Tournament and their chance to see their father again!