The Earth embassy on Vulcan is bombed, killing 31 humans and 12 Vulcans. Enterprise is called to the planet to help investigate, but the Vulcan High Command already suspects a dissident religious faction known as "Syrrannites." T'Pol learns from her husband Koss that her mother T'Les has been forced into hiding to avoid arrest — because she is a Syrrannite. Koss also brings her a mysterious heirloom containing a map. Believing this is a message from T'Les, T'Pol and Archer set out to follow that map across a treacherous desert, without the High Command's knowledge
