The Tenth Doctor meets one of his previous incarnations.
Did You Know?
In interview with Doctor Who Magazine that was released prior to the broadcast of Time Crash, writer Steven Moffat
confirmed that "Time Crash" is considered part of the official Doctor Who canon. (There is a cutaway at the end of the preceding regular episode, "Last of the Time Lords" which allows for "Time Crash" to occur between that episode and "Voyage of the Damned".) See more
And the Master. Oh! He just showed up again, same as ever.
Oh no, really? Does he still have that rubbish beard?
No, no beard this time. Well, a wife.