“There But for the Grace of God” is episode twenty of season one of Stargate SG-1.
SG-1 arrive at a world in a facility that looks pretty advanced, but has also been badly damaged by Goa’uld weaponry. Teal’c sees a symbol that says that the world has been devastated by the Goa’uld. The team decide to leave, but Daniel activates something that has an unexpected effect, and he can’t find the rest of the team. When he returns through the stargate to Stargate Command, nobody recognises him and General Hammond is only a Colonel – and those are only some of the differences.
Daniel has been transported to an alternate universe by the device he touched – although he takes a while for anyone to figure this out – a world in which he was never a part of the Stargate programme.
The Earth he is on is in the process of being destroyed by the Goa’uld. When he returns back to his universe, he is in possession of valuable knowledge that will help his Earth in their battle against the Goa’uld.
This is the first episode that alternate universes appear in – but not the last; they occur in more episodes and other series in the Stargate franchise.