Haven was a M-class planet orbiting Beta Cassius. It was inhabited by a humanoid civilization. The planet was renowned for its tranquil beauty to the point that many thought it possessed mystical healing powers, though this claim was unsupported by scientific evidence. According to legend, Haven "has been known to mend souls and heal broken hearts."
In 2364, the USS Enterprise-D visited Haven to receive Lwaxana Troi and Steven Miller's family. Soon after, a Tarellian starship carrying the last survivors of a plague approached the planet, seeking its reputed healing powers. The ship bypassed the system's stargate and failed to reply to attempts at communication.
First Electorine Valeda Innis entreated Captain Jean-Luc Picard to destroy the Tarellian ship before its crew could disembark and spread the plague to the population. Thanks to the intervention of Wyatt Miller, the Tarellians changed course. (TNG: "Haven")