I woke up with the familiar sound of the incoming tide washing relentlessly against the rocks and the smell of musty potatoes in my nostrils.  I struggled to free my hands which were secured behind me but it was no use.  I kicked my legs but could barely move them an inch as they too were tied.  My back was against a wall of rock and I could feel a length of chain digging into my spine.
'Help!'  I quavered.  'I'm hog-tied in the tunnels with a potato sack over my head and the tide's coming in!'
'So am I!' cried Geoffrey.
'Never fear Tuppy.'  Suddenly a bright gap appeared, and a pair of nail scissors flashed in the evening sun.  The potato sack fell to my shoulders and I breathed clean, must-free air for the first time in - well, I wasn't sure how long because I couldn't remember anything after receiving the 'thud' on the back of my neck.
I blinked a few times and looked around me.  Someone wearing a yellow 'hi-viz' jacket was sawing away at the potato sack next to me with the nail scissors.  For a panic-stricken moment I thought it was Tuppence in his yellow oilskin, or heaven forfend, Alexa, but no - from the cloven feet and the sword-stick I could tell it was the Tupfinder General.
'Just as well I had Mrs T-G's nail scissors on me,' he said as he freed Geoffrey. 'I'd forgotten they were in my waistcoat pocket.  I must have popped them in there after I trimmed my eyebrows this morning.  If I hadn't had them I'd have had to use the business end of the sword stick and it's blunt.  I'd have been sawing away for ages.  We'd better get out of here before they get back.'
'They?'
'Tuppence and Alexa of course.  They want all us oldies out of the way.  It isn't only you two, and it isn't only them.  Can you both walk?'
'I can fly,' said Geoffrey.
'Of course.  All right - you fly over to the next tunnel and see if it's empty.  We'll follow along.  Fly back and let us know if anyone's there and if so we'll try Plan B.'
'What's Plan B?  and why must we go to the next tunnel along?  why can't you take us to Tupfinder Towers?'
'For goodness sake Tuppy.  Don't you know anything?  Don't you follow The News?  Don't you read the People's Bugle?'
'No.  I don't like News.  Unless it concerns me directly, and hardly anything ever does, thank goodness.'
'Well, I'll -'
'The next tunnels full of huge boxes T-G,' gasped Geoffrey, who had just flown back in. 'I couldn't read the labels in the dim light so I don't know what's in them.'
'I do,' said the T-G grimly,' It's stockpiled medication and probably other stuff as well. We must be right next to Dr Wilson's cached supplies.  Were there any - creatures in there?  anything - living?'
'I didn't see anything.  But I couldn't be sure. Because of all the boxes I couldn't see right to the back and it was awfully dark.  I was frightened T-G. I don't mind telling you.  It just didn't feel right and there was a funny smell, sort of like -'
'Like marzipan?' said the T-G.
'Yes!'
'Hmm.  Well, I think it'd better be Plan B after all.  Just in case.'  The Tupfinder General threw me a yellow 'hi viz' jacket and a length of stout rope.  'Put that on and tie the rope to your waist Tuppy.  We're going to have to climb.  I'll tell you all about The News when we get there.'
'Where's there?'
'Just shut up and do as I say.'
'Charmed I'm sure!  What do you make of that Geoffrey?  he's telling me to shut up!  did you ever hear the like!'
'He's right Tuppy,' said Geoffrey, struggling into his own little yellow jacket, 'Have you forgotten that we were bumped on the head by your own awful nephew just last night and hogtied with potato sacks over our heads?   Get a move on and tie that rope round.  We've got to get out of here before they come back.'

more later