The trailer starts with a camera flying through space, with various sci-fi mumblings over the radio. Eventually, we see some debris, including a broken Mass Effect relay. The trailer ends with an Asari — presumably Liara — trudging through the snow on an icy planet. With a dead Reaper in the background, she picks up a piece of N7 armor and looks at her comrades in the background.
Commander Shepard — likely the owner of that N7 armor — dies at the end of Mass Effect 3 regardless of the choice players make. The Mass Effect relays that allow inter-galaxy travel also deactivate completely.
This sequel looks to explore a galaxy after Mass Effect 3, where Shepard used The Citadel to fundamentally change all life in the universe.
The teaser simply ends with “Mass Effect will continue.” The official Mass Effect Twitter account tweeted that BioWare is in pre-production on what could likely be Mass Effect 4.
BioWare confirmed a new Mass Effect project was in the works in November, saying that a veteran team of developers was developing the new game.