Barbara has been infected by the deadly insecticide but keeps her condition secret. Despite their small size, the travellers attempt to alert the authorities to Farrow’s murder.
The Doctor and his friends witness Forrester murder Arnold Farrow. Ian and Barbara watch as one of the ‘giants’ empties the sink in which the Doctor and Susan are hiding.
An accident in flight leads to the TARDIS and the travellers being miniaturised. Now only an inch high, the Doctor, Barbara, Ian and Susan explore an English country garden.