<img src="https://assets.podomatic.net/ts/84/fe/60/pisgahscience40937/3000x3000-714x714+70+3_12508324.jpg" alt="itunes pic" /><br />A mysterious teenager has arrived on board the TARDIS. As one old friend leaves, another rejoins them. Meanwhile, the Doctor receives a mysterious phone call from someone who claims they know him. Are they a liar? Or an old friend? And who is on the spacecraft staying motionless above the world of Nova Alturius? And what could they possibly want?