Representing an ambitious and potentially risky expansion of the synergistic DC-CW-Warner Bros. TV connection, “DC’s Legends of Tomorrow” not only assembles a super-team but casts it into an elaborate time-spanning plotline. As an added degree of difficulty, the group relies on somewhat obscure characters, albeit with the benefit of having introduced them in the context of its “Arrow” and “The Flash” franchises. The resulting hour is certainly impressive from a visual standpoint, with bountiful dollops of action. Yet based on the mix of personalities, this colorful series will have to improve significantly to achieve even near-legendary status.

Certainly, no one needs to give producer Greg Berlanti and the “Arrow”/”Flash” brain trust charged with presiding over TV’s DC flame any notes about raising the stakes. The action opens in 2166, where the immortal villain Vandal Savage (Casper Crump) has surpassed all previous despots and dictators by conquering the entire world, prompting time master Rip Hunter (Arthur Darvill) to seek permission to travel 150 years into the past, enlisting an octet of super not-exactly-friends to thwart him by changing the course of history.

The recruitment process goes by pretty quickly, as Hunter brings together Firestorm (Franz Drameh/Victor Garber), the two-in-one hero; the Atom (Brandon Routh); Hawkgirl (Ciara Renee) and Hawkman (Falk Hentschel); the assassin White Canary (Caity Lotz); and the bad-guy duo Captain Cold and Heat Wave (Wentworth Miller and Dominic Purcell, respectively), who, with their sneering larcenous streaks, are essentially presented as the ill-tempered comic relief.

“The Flash,” to its credit, has managed to play around not only with amending timelines but also with an alternate universe, without slipping over into a level of silliness that would chase away viewers. At almost every turn, “Legends” seems to double down on that, even having Garber’s character — in a very “X-Men: Days of Future Past”-like riff — join the gang in traveling back to the 1970s, and encounter his younger self.

For the most part, it’s all played as big, fun and slightly goofy, albeit with the dark streak that the world’s blighted future hangs in the balance. What “Legends of Tomorrow” hasn’t mastered, at least as it races to establish its premise in the two previewed hours, is the elusive and vital chemistry among these characters that’s necessary to transform an ungainly assemblage of costumed heroes into more than just a group that randomly kicks as much butt as the budget allows.

Of course, there’s a long history of bickering super-teams dating back to the Fantastic Four, but even with the narrower niches that modern TV permits, translating that into a series remains a formidable challenge. On the plus side, “Legends” has a big toolbox from which to draw, and the courage to embrace its comic-book origins. Even so, it will require finding the right balance of action while fine-tuning the character interactions if the show hopes to have a future that extends far beyond tomorrow.