*** Contains spoilers ***
Jack: "There is a secret hidden underneath the rift. A shadow from the oldest universe of all. Syrieth - the death feeder. She's been trapped since before there was such a thing as time."
That's all shorthand - or longhand rather - for a story about ghosts.
The thing that I'll remember it for though is that wikipedia had indicated this radio episode to be set following the TV story Children Of Earth. As a result, the presence of Ianto (who died in that story) in the first scene probably meant one of two things - either that wikipedia was wrong, or that Ianto was to be revealed at the end as a ghost.
It was the latter. Dang - that would have been a fantastic twist, and only really possible upon its first broadcast. (few science fiction fans will listen to any audio spin-off without first checking where the episode comes)
The irony for me was that the episode seemed to work much better without this reveal. It raises too many unanswered questions, like why Ianto's dad never told him that he was dead, why he arrived before all the other ghosts, why he doesn't know he's a ghost, why Ianto is more missed by Jack than his grandson, where Ianto gets his headset from, why he doesn't turn it on, why he never notices that it's not turned on, and what Jack is doing back on Earth. Really, just ditch that twist and set it before his death with the other episodes in this series already. You know it (would) makes (more) sense.
Not to mention what a cliché a character turning out to have been dead all along has been ever since that movie a few years back. You know the one. It's so famous for that ending that I don't even have to name it. Or see it.
I've been listening to these three radio episodes - at the moment still referred to by their broadcast title of The Lost Files - whilst getting on with other things, but come the final conversation between Jack and Ianto, I just had to put down what I was doing and pay attention. It's just the sort of talky scene that TV today doesn't have time for, and to hear the two having a chance to say a proper goodbye was an important moment in the series' history.
There was a point where my interest began to wane though, and when Ianto sacrificed his reanimated life to save the already immortal Jack, well, that was just utterly, utterly stupid.
Again, just set it before Children Of Earth and let Jack blow up the building already.
Otherwise, as a listener, you're really better off just turning off after the first half hour and making up your own ending.
Like the TV series that inspired it, this episode could have been much better had it not been trying so hard to prove itself.