The TARDIS materializes on the sea this time and the Doctor and crew have to use a raft to get to shore.  The are tranquilized by security guards when they reach shore since they are at a restricted facility.  The Doctor later learns that there have been some unexplained problems at the facility.  The pressure in the pipes is fluctuating and it is later learned that a parasitic form of seaweed has been drawn into it.  The seaweed can release poisonous gas or a foam that allows it to control the minds of the people that it touches.  The weed spreads around the rigs.  The Doctor discovers that it is susceptible to Victoria's screams and that high pitched noise han be used to combat it.  Victoria decides to stay on Earth at the end of this adventure.