Doctor Who: Expiry Dating (The Tenth Doctor and River Song, #1.1)

The first time the Doctor met River Song, he saw her die. And now she’s asking him on a date. Well, not a date, exactly... More of a mission.
But the Doctor isn’t at anyone’s beck and call. Or so he thinks. With billions of lives hanging in the balance, can the Doctor afford not to do whatever River wants? Whichever one of him she asks?

David Tennant (The Doctor)
Alex Kingston (River Song)
Peter Davison (The Doctor)
Colin Baker (The Doctor)