Sisko (and Keira?) by time travel shenanigans ends up in the grim dark future of 2024, where capitalism and loss of solidarity has lead to rampant homelessness and unemployment, and disregard for those affected. The homeless people are forbidden from being in public except in heavily guarded 'sanctuary districts', i.e. concentration camps.

Bell, a black guy and political agitator living in a sanctuary district, gets killed shortly after Sisko arrives. Sisko remembers from history that him being shot by police let to riots that resulted in a leftist movement that put the world onto the path towards fully automated luxury space communism, but Bell got shot too soon, so it's up to Sisko to impersonate him.

Character drama happens, Sisko waxes poetically about solidarity and kindness, and eventually Sisko gets shot and then timey wimeys back to the 24th century. He looks in the archives for newspapers of the riots and sees his own face as Bell.