Translation:The woman finds the master of the enchantments.
the woman finds the ____ master could just as easily be filled with spell's (seetero) as spells' (seeteroti)
what's more, when typing the English version, it marks « spells' » as a typo, suggesting « spells ». Three's no way to report it because a typo isn't considered a miss, so the "my answer should be accepted" option doesn't appear. This happens with other English possessive plurals, too.
Can always report, that is what the "There is another problem with this exercise" field is for