Law of Surprise, a custom as old as humanity itself, is the price a man who saves another can demand. It is a request for something which neither the saviour nor the saved knows the nature of, until the saved man returns home. Typically this ends up being a child born while the father was away and more often than not, a boy — though there were at least two girls, Pavetta and Ciri.
"the first thing that comes to greet you"
When requesting "the first thing that comes to greet you", the price could be the likes of a dog, a halberdier at the gate or "a mother-in-law impatient to holler at her son-in-law when he returns home".
"what you find at home yet don't expect"
When requesting "what you find at home yet don't expect", the price could be a lover in the wife's bed, but sometimes, a child.
Involving Geralt of Rivia
- King Roegner of Cintra, as a reward to Urcheon of Erlenwald, promised him "whatever he had left at home without knowing or expecting it". This was his daughter Pavetta, for whom he officially returned 15 years later, although they had in fact already met
- →These events are told in the short story A Question of Price.
- After curing him from his curse, Duny offered whatever Geralt of Rivia asked for. Geralt asked for "that which you already have but do not know": Pavetta and Duny's daughter Ciri.
- Geralt unknowingly names Ciri as his reward a second time when he saves the life of Yurga, for while the man was away, his wife took in the orphan girl.
- Geralt himself is a victim of the Law of Surprise. It was because of the Law of Surprise that Geralt was taken in as a Witcher.
From legends and tales
- As a child, the legendary hero Zatret Voruta was given to the dwarves because he was the first person his father met on his return.
- Mad Deï demanded a traveller give him what he left at home without knowing it. This was the famous Supree, who later liberated Mad Deï from the curse that weighed him down.
- Zivelina became the Queen of Metinna with the help of the gnome Rumplestelt, and in return promised her first-born. Zivelena didn't keep her promise when Rumplestelt came for his reward and, by using spells, she forced him to run away. Not long after that, both she and the child died of the plague.
In The Price of Neutrality premium module
- The book series fills in more information about The Law; When Destined child turned out to be a girl - a witcher would trade her for a boy with Dryads - the only exception was Ciri whose bond with Geralt was so strong that it overcame the dryads objections.
- In Slavic mythology, The Law of Surprise was originally a form of payment for a devil's service.