Few productions at Cartoon Network have been hyped more than Infinity Train, believed by many to be the network’s next Adventure Time if they can pull off the promise in the premise.

Today, after months of silence, CN uploaded a new Infinity Train trailer to the Internet….but to see it, you have to work for it.

If you visit cartoonnetwork.com/infinity train, you’ll get a glowing trail cursor and a glowing “ENTER” button. Push it and be transported to a floating space void with eerie synth music and a lopsided keyboard in front of you. Your challenge is to play the four-note stinger that can be heard at the beginning of all CN’s previous previews for this series. If you need help, the notes are D, B, G, and F#.

I still couldn’t do it. Good thing this tweet exists.

It was only supposed to be a quick trip to Coding Camp in Wisconsin. But when young Tulip ends up boarding the wrong train, she becomes trapped within its cars — and the train seems to have no end. Fortunately she quickly meets two friends, one canine and one robotic, and they set off to solve the mystery of the Infinity Train, and by doing so, find a way to get Tulip off it.

Infinity Train is still scheduled for a vague 2019 release. CN keeps these things close to the chest — we didn’t know when Mao Mao would show up until the second it did.