Humanity has finally done it.  Scientists at a base in London are about to open a Wormhole to a far off sector of the galaxy.  The implications are enormous, and nothing will ever be the same again.  Mankind will finally be able to travel amongst the stars.

But the Doctor knows something is wrong.  Mankind shouldn’t have this kind of technology, not in the early 21st century.  But who gave them the technology?  What for?  Why is UNIT being kept in the dark?  And why exactly does the head of the Ministry of Defence have a Sontaran hiding in his cupboard?