This is a Mystery cache, dedicated to my favorite writer, author of 66 detective novels.
When on mystery's location, you will find her monument there. The Queen Of Mystery wrote 2 of her famous works while on holiday here in February 1927. She also wrote a novel featuring surroundings of La Paz, a significant house casa Cólogan she has been visiting and the nearby beach. Heroes of the novel has been looking down the clifftop and heroine's husband even died there. You will be following writer's footsteps and visiting places she was staying and described in her novel.
The question is:
How died heroine`s late husband?
Answer: he * * * * * * *.
Write every letter as a number, according to its place in the Latin alphabet, and count the total (S).
Final spot you will find at the coordinates: N28°24.PQP W 016° 32.QQR, where MNOPQR = S*S*S – 3.
Avoid the mugglers and ... good luck!