The series is structured into major sagas that track the evolution of its characters, particularly the rivalry between Goku and Vegeta. You can find a comprehensive breakdown of these arcs on the Dragon Ball Wiki .
As the battle rages on, Goku begins to tire, and Frieza gains the upper hand. Just when all hope seems lost, Goku's son, Gohan, arrives on the scene, using his own hidden potential to help turn the tide of the battle. With Gohan's help, the Z-Warriors manage to hold their own against Frieza, but it's unclear if they'll be able to defeat him once and for all. dragon ball z episode