There's probably a spoiler here. Who knows? People spoil so much more easily than they used to.
As a general rule, martial arts films are fairly stupid. Animated martial arts films are, as a general rule, terminally stupid. I will be the first to admit that the Dragonball Z material, which is extensive, isn't the most absolutely stupid, although at times it comes perilously close.
Those who are unfamiliar with this subset of the genre, the Dragonball series concerns the dynasty of muscle-bound martial arts superheroes founded by an alien (Seiyan), Goku. He was sent to Earth to destroy it as an infant, but forgot all about it an became the closest thing to Li'l Abner seen in modern anime (he's hugely strong, mild of manner, and innocent to the point of impraticality.
You would think the series would actually be about "Dragonballs". Well, it sort of is, occasionally. These little orange balls with stars on them, if collected together, allow the possessor to call up a gigantic magic dragon that will grant a wish. At times where's a lot of plot business connected with rivalry in getting the balls. However, at other times the dragonballs completely disappear. This is one of those times.
Instead we get lots of martial arts and of course the other thing associated with Dragonball Z, overabundant and overdone "comic relief" -- which is too self-consciously "comic" and from which there is little relief. A lot of this is provided here by a stock Dragonball character, Hercule. The reader is referred to an other "Hercule", Clouseau's assistant in the early Pink Panther films (and clearly a parody of a third Hercule, namely Poirot). The Panther Hercule is only marginally brighter than Clouseau ... the Dragonball Hercule is more than marginally less bright. Despite the clearly greater martial powers of the Goku dynasty and other fighters, he always manages to retain the title of World Martial Arts Champion through some fluke. For a while, Hercule has no idea he's benefited from other than his own skills, but by the time of the "Bojack" film, he's well aware of his position at the bottom of the totem pole.
You won't see much it here, but Dragonball comedy tends to use laughable names for its characters, particularly villains -- such as the perennial Garlic Jr.
As is usual with Dragonball, there is a martial arts contest and it turns into a serious threat to the continued existence of Earth. The threat is then dealt with (with lots of cliffhangers) by a member of the Goku dynasty. (By the way, nobody ever explains how the continued mating of the Goku dynasty members with Earth people fails to produce weaker and weaker offspring. If anything, this genetic dilution seems to produce stronger results. On the other hand, expecting things in this series to make any real sense in the real universe is very, very foolish.
The "Bojack" film is fairly harmless and will no doubt fascinate kiddies whose educational prospects are limited. Nevertheless, I urge you not to buy this turkey. The reason is simple: it is preceded by 2 blatant and obnoxious commercials that can't be bypassed. If you want to watch the film, you have to watch the commercials.
Shades, we hope, NOT of things to come.