If Marvel’s Agents of S.H.I.E.L.D. is not on your must-see list, you’re easily missing one of the most fun adventures on all of television, broadcast or cable. This week, Lady Sif (Jamie Alexander) returns and helps Team Coulson deliver a crossover that brilliantly expands the Marvel Cinematic Universe on the small screen, fully establishing a world which breathes and grows in its own time, at its own pace.

There are no awkward references to Thor or Loki in this week’s episode, “Who You Really Are” – written by executive producer Drew Z. Greenberg (Arrow, Warehouse 13) – or mentions of any of the massive battles which took place during recent MCU film installments. This is simply not a name-dropping episode on the small screen, in any way – let’s make it clear. What it is, however, is so much more: it is the world of the MCU brought to life through Coulson (Clark Gregg) and his team. For the first time it feels as if the series is now being used to explore many familiar elements from Marvel’s billion-dollar movie franchises, in-depth (in addition to the developing its own story concerning Inhumans).

As audience members, we now get a better look at a member of the Kree – memory-wiping Kree warrior Vin-Tak (Eddie McClintock; Warehouse 13), to be exact – who faces off against Lady Sif (whose own parole officer duties in Asgard require her to find out what the fellow is up to on Earth). Vin-Tak and Sif are enemy species, inherently, and McClintock’s Vin-Tak is essentially TV’s version of Drax the Destroyer (Dave Bautista), mono-tone jokes and all – and equally as successful.

Eddie McClintock now matches Patton Oswalt as the series’ most successful guest star and non-recurring character (hopefully, he’ll return at some point). Agents of S.H.I.E.L.D. can certainly use a bit of humor these days, especially now that their resident personalities Fitz (Iain De Caestecker) and Simmons (Elizabeth Henstridge) are far less fun, far more serious, and far more dangerous than they were in season 1.

Greenberg, this week’s writer, is known for the season 2 femme fatale episode “Face My Enemy” featuring Melinda May (Ming-Na Wen) vs “Melinda May”; with “Who You Really Are”, he gets to highlight the characters most episodes overlook. Here, there are no high-tech face masks or missions; however, the story (once again) shows the strength of the series’ female cast members – who have often been under-served since the series’ beginning. Fortunately, it appears that Skye’s new super-powered story-arc may help drive more character development to those around her. After all, Skye can’t be both the strongest (as “Quake”) and weakest (unable to control “Quake”) female character – especially while May can still take her in a fight.

As this week’s title suggested, we found out that the Kree visited Earth millions of years ago. The Kree were experimenting on a young human race and creating a lineage of mutants with superpowers, to use them as weapons in their own battles. Skye and Raina (Ruth Negga) represent two of many who now exist. Though many comic book fans are familiar with the origins of Inhumans, it is exciting to see how the story leverages Vin-Tak and Lady Sif to help sell the story. In a sense, the producers figured out that it’d better for the MCU to play in the world (and logic) of Agents of S.H.I.E.L.D., than to have Agents of S.H.I.E.L.D. embarrass itself with superhero name-checks – or, as is were, cleaning up Thor’s garbage (see: Season 1, Episode 8 – “The Well”).

Ultimately, much of the success of this week’s episode – aside from story reveals – is that Lady Sif and Vin-Tak didn’t need to be in this episode in order to tell the origin story of Skye, Raina and the Inhumans. The success of Agents of S.H.I.E.L.D. can be attributed to the series’ writers having the ability to write around everything in the Marvel Cinematic Universe they’re not able to use – which is “everything”, essentially.

For Vin-Tak, a Kree, and Lady Sif, an Asgardian, to be part of a subtle side story so successful, so nonchalantly, it means that whatever the driving force of this series is now, the show’s writers are comfortable flexing their strengths and incorporating cameos (which can be disastrous for the series, if they are not executed correctly).

Over the next few weeks, Agents of S.H.I.E.L.D. will CONTINUEarrow 10x10 Agents of S.H.I.E.L.D. Proves MCU Crossovers Are Better Without Avengers to evolve itself until it’s able to find a comfortable place to unleash the flurry of cliffhangers it has at its disposal. Thing is, right now, even though previous key players such as Ward and (thankfully) Deathlok are nowhere to be found, Agents of S.H.I.E.L.D. feels like a complete series. Still, that doesn’t mean everyone isn’t looking forward to the return of two-face Ward (or however many “faces” he’s up to now).

Agents of S.H.I.E.L.D. returns next Tuesday with “One of Us” @9pm on ABC. You can CHECKarrow 10x10 Agents of S.H.I.E.L.D. Proves MCU Crossovers Are Better Without Avengers a preview of next week’s episode below: