The post has been making the rounds on Tumblr for nearly a full day, with no tags, no explanation, and no lead-in—only the injunction, “Shhhhhhh!”

And that’s exactly what Tumblr has done.

We won’t link you to the Tumblr post, which is so unassuming that it’s easy to skim past, which might explain why it’s racked up only 10,000 views or so in the 18 hours it’s been up.

Nor will we show you the YouTube video that the post links, a blurry sequence apparently filmed on a phone. The footage, prominently featuring Doctor Who actor Noel Clarke, might initially confuse viewers wondering if it’s the latest Who Christmas special—except for the sudden appearance of Benedict Cumberbatch.

Is it a surprise Wholock crossover?  Even better: it’s a blurry (but still exciting) cam leak of the nine-minute Imax trailer preview of Star Trek: Into Darkness.

With excitement over the freshly-dropped Star Trek trailer still high, it’s a wonder that the Tumblr leak only has ten thousand notes or so at this point—but word of mouth has traveled fast, and the video’s hit counter on YouTube is currently stuck at 33,405 hits, a sign that viewers are tuning in right and left.

But true to the poster’s request, no one is tagging the post or openly reacting to it on Tumblr.

The video appears to have been uploaded by an obvious Star Trek fan who reacts with delight through the film’s opening sequence and announces, “I’m so done,” in true Tumblrite fashion when the ten minute preview concludes.

In the opening scene, Benedict Cumberbatch approaches Noel Clarke’s unknown character with an offer to save his dying daughter’s life.

Then we’re whisked to a completely different location as we follow Captain Kirk and Dr. McCoy on a madcap chase through the woods of an alien planet, pursued by the locals on the brink of an erupting volcano.

Spock launches himself into the mouth of the angry volcano in order to work his Vulcan science magic to prevent the destruction of the planet.


 

Kirk and McCoy leap off a cliff and dive underwater, into the waiting arms of the Enterprise.


 

There’s just one problem. The ship is forced to take off to save itself, without rescuing Spock, who argues with Kirk—complete with the patented J.J. Abrams lens flares, of course—to leave him behind while a devastated Uhura looks on.


 

Will the Enterprise be able to save Spock?  We’ll have to wait til May to find out.

Fans who aren’t satisfied with the blurry online version can see the real thing at selected Imax 3-D showings of The Hobbit.  Other fans, who haven’t realized the extended preview is out yet, are flailing over a second trailer, just released today.

For now, the real wonder is in watching Tumblr quietly pass the extended preview around, right under YouTube’s nose, all on the basis of the uploader’s request: “seriously don’t tell anyone.”

But at 11,000 notes and tens of thousands of YouTube hits, it’s safe to say the secret is out.

Screengrabs by Aja Romano