You know how it goes – you book a lovely holiday with your mates full of sun, sea, and surf, only for your boss to cancel it and send you on a mission to the centre of the Earth. Oh, what’s that? You’re not familiar with that issue? Well, this is Stingray, so you’d better get used to that sort of thing happening. Subterranean Sea is one of those points in the series when the production team have just had to throw up their hands and declare, “Who cares if it makes sense? Let’s just have fun with it and hopefully the people watching at home enjoy it too.” And, d’you know what? That sounds like just the right attitude to me.