Every guest gets a code that dies at eleven on checkout day. One code from 2019 has been deleted twice and still opens the door, and the log shows it used in the gap between one booking and the next.
I let a two bedroom cottage on the coast. It is my mother's old house and I could not sell it, so it pays for itself and a bit more, and I have run it since 2018.
The lock is the thing I need to explain, because everything here is the lock.
It is a keypad deadbolt, a well known brand, with a bridge to my wifi so I can manage it from my phone. Every booking gets its own code, generated by the booking system and pushed to the lock, valid from four in the afternoon on the arrival day to eleven in the morning on the departure day.
At eleven the code stops working. Not because somebody remembers to turn it off: the code has a schedule in it and the lock enforces it.
And the lock keeps a log. Every entry, every code used, by name, with a timestamp, and it holds a thousand events before it starts overwriting. I have exported it every month for six years because my insurer likes to see it.
Code 4791 belonged to a family who stayed for a week in the August of 2019.
Perfectly nice, left the place tidy, left a note about the tide times being wrong on the fridge magnet, which they were.
Their code expired at eleven on the Saturday they left, the way they all do.
It has been used two hundred and nine times since.
Here is how the log reads, and it is always the same shape.
The last guest of a booking leaves. There is an entry for them at some point on the departure morning, usually the door being locked from the outside as they go, which the lock records as a manual lock.
Then, between four and forty minutes later, there is an entry: code 4791, door unlocked.
Then nothing for a while. Twenty minutes, an hour, once nine hours.
Then a manual lock from the inside, which is a different event type, because the lock knows which side of itself the thumb turn was moved from.
Then the cleaner arrives on her own code and the place is exactly as guests left it.
I have deleted that code twice.
The first time was in 2020, when I noticed it in a monthly export and assumed I had never removed it. I deleted it in the app and got the confirmation and checked the list and there were eleven codes on the lock and 4791 was not one of them.
It was used the following Tuesday.
The second time was in 2021 and I did it properly. I did a factory reset on the lock, which wipes every code from the module itself, and I set it up again from scratch and entered six codes by hand on the keypad, and 4791 was not one of the six.
It was used nine days later.
Everything I have checked, and I have spent real money on some of it.
The lock. Replaced in 2022. New lock, different model, same brand. It carried on. Replaced again in 2023 with a completely different manufacturer and a different app, and the new lock has never had a code 4791 programmed into it in its life, and its log contains the words that manufacturer uses for an unrecognised code, which is invalid entry, and it contains nothing at all in those gaps.
That is the one that stopped me sleeping properly for a while. The new lock does not record 4791 being used, because 4791 means nothing to it. What it records in those gaps is the door being opened.
Not forced. Not the keypad. The bolt going back and the door opening, with no code, which on that model is what the log looks like when somebody opens it with the mechanical key override.
There is one key for that override. It is in a bank in town in a deed box and I have signed the register every time I have taken it out, which is four times in three years, and I have the dates.
None of them line up.
The wifi. Both locks talk to a bridge, and my first thought was somebody on the network, so the network was rebuilt: new router, new password, guest wifi on its own VLAN, and the bridge on the private side with nothing else on it. An engineer did it and charged me two hundred pounds and it made no difference.
The neighbours. There are two cottages either side, both let, both managed by other people, and the one on the left has been empty since 2022.
The cleaner. She has been with me since the start, she is my cousin, and she has her own code, and her code is in the log where it should be. I have never asked her about this and I never will, because I know what that question does to a person.
The bookings. I did wonder whether a guest was coming back, so I compared the two hundred and nine dates against every booking I have ever taken. Nothing. Not a returning guest, not the day before a booking, not a pattern in the season.
The only thing that predicts it is the gap. If there is a night with nobody in the house, it happens on the first night of that gap, ninety per cent of the time.
What is in the house afterwards.
Nothing, and that needs saying, because it would be an easier story to tell if things moved.
Nothing is taken and nothing is left. The cleaner has never reported anything. I have gone in myself perhaps thirty times the morning after, on my own, and the house is a clean empty house that smells of the sea and the plug-in in the hall.
Twice the kettle has been warm.
I have written that sentence and looked at it and I am going to leave it, because both times I checked the switch and both times it was off at the wall, and the second time I put my hand flat on the base of it and it was the temperature of something boiled about an hour before, and I stood in that kitchen for a long time working out whether I could be wrong about that, and I could not.
What I do now is nothing, and I have made my peace with it in a way I would not have believed in 2020.
The house is let forty two weeks a year and the reviews are good and it pays my mother's care home fees, which is the only fact in this that anybody needs in order to understand my decisions.
I have stopped exporting the log. The insurer gets the annual summary and the annual summary is a count of entries, and the count is right.
And I have changed one thing about the way I run it, which is that I do not leave gaps any more if I can help it. I price the odd single nights at almost nothing to fill them, and my accountant thinks I am soft, and I let him think it.
It is very rare now. Four times last year.
All four were January, and all four are in the log as the door opening, at some point in the evening, with no code.