The location of Zeno Terpstra's castle can be seen from episode 320 of season 3 - part 2, or at least the front of the castle. Zeno Terpstra's room, which is part of the castle, can be seen earlier in episodes 238-239, 266-267, 269, 302-303, 306-309, and 312 of season 3 - part 2.
In season 3, Zeno Terpstra is in bed at home, very ill. He likely has some residual effects from being poisoned by Raven. He wants the Tear of Isis and is helped by Rufus Malpied.
Zeno Terpstra's study is located in the Zinnick Bergman Museum, but in reality, his study is in Wissekerke Castle.
Filming was also done around the castle and on the grounds of Wissekerke Castle.
The filming took place at Wissekerke Castle in Beveren-Kruibeke-Zwijndrecht, Belgium.
