This episode was originally recorded to end the first series of 13 episodes, but a second series was never seriously considered, so this episode was brought forward in the order. The order we're doing here is as close to filming order as possible, but with necessary exceptions, like this one.
The Prisoner awakes to.find The Village empty, deserted, everyone has gone and left him alone. He builds himself a raft, sets sail, runs into gunrunners who dump his body in the sea, but our hero survives and ends up in England. His London home is now inhabited by the elderly Mrs Butterworth, who also drives his Lotus 7 car, but she generously lends the car to The Prisoner, who returns to his old bosses and sets in motion a mission to find The Village.
Of course he ends up back in The Village, that's obvious or they'd be no more episodes, but a shock awaits him on his return.
Why he was allowed to leave and how events unfolded when he returned reveals something really important about the reality of the events in this series.