Murder in the Border Castle (#4)

The traces of a mysterious artifact that extracts magical power lead to the border castle of Garth de Mont. The secret service commissions the wizard Skai and his friends to go there disguised as travelers and identify the client, but on the very first night in the castle, a murder occurs. A servant is poisoned, and this is clearly not an accident: is someone covering their tracks or trying to frame Skai? He will have to deal not only with the crime but also uncover many family secrets of the castle's inhabitants.