The official Overwatch Twitter account released a on Monday that appears to hint at a possible upcoming event.

The tweet shows an access page for the Overwatch Mission Archives. The screen is specifically keyed to “File 00382 – King’s Row Uprising.” King’s Row is one of the map’s in the game that takes place throughout the streets of London. The map is also the home map of the hero Tracer.

The file goes on to state that the file was entered into record seven years ago. This seems to suggest that something from the game’s past might be at the center of a new event. This would also be the first event to play off the game’s internal story rather than be centered on a holiday or real-world event.

The video also contains a few other messages behind the prominent one that repeatedly blink in and out of focus. One appears to be some sort of state-of-the-art research center. The image is obscured, but certain words can be made out, such as “building,” “future” and “Turing.”

The other message is very clearly a poster advocating “mandatory robot registration.” Within the world of Overwatch, there was a war between humans and robots that ended in an uncomfortable peace.

The King’s Row Uprising is an event unheard of before in Overwatch lore, though a story video released during the game’s promotional campaign may shed some light on the matter.

The file is classified as confidential, but the final line reads that “declassification” will occur on April 11.