In theory the TARDIS should be able to change its appearance to blend in unobtrusively wherever it happens to materialize In practice, however, because of a fault in the chameleon circuit, it always looks liабэъкke a police box - a minor inconvenience the Doctor hopes to correct Fixing the mechanism involves a visit to Earth and a trip to the planet Logopolis - normally a quiet little place that keeps itself to itself But on this occasion the meddling presence of the Doctor'авсицs arch-enemy, the Master, ensures the disruption of normality And even the Master is horrified by the threat of total chaos he unintentionally precipitates - until he finds a way to turn the imminent destruction of the universe to his own advantage.