On Boxing Day, 1900, The Hesperus arrives at Flannan Isle to relieve the lighthouse keepers.
She sounds her steam whistle to alert the keepers but there is no response.
The telegram from the captain reads 'managed to land Moore, who went up to the Station but found no Keepers there.' What the relief keeper did find was the lamp prepared, the washing up done, but the clock stopped, the fires out and the last entry in the diary dated 15th December.
The three lighthouse keepers had vanished.
The mystery of their disappearance has fascinated people ever since - not least artists.
Wilfrid Gibson, a friend of Robert Frost and Edward Thomas, wrote an atmospheric poem on the subject, published in 1912, that intrigued the public of the day.
Peter Maxwell Davies has written an opera, there's a song by Genesis and an episode of Dr Who all based on the mystery.
The poet Kenneth Steven visits Flannan and relates what he sees there to Wilfrid Gibson's poem.
Using the original reports - the telegram giving the first news, a letter written two days later by Joseph Moore, the official report by the lighthouse superintendent - with archive recordings and expert opinion, he pieces together what happened, and interweaves all these elements with the wind, the waves, and the silence of the deserted isle.
Producer: Julian May.
Kenneth Steven probes the mystery of vanished lighthouse keepers and the poem about them.