Wis. Stat. § 75.24
Every action brought or claim presented against any county for the recovery of any sum of money on account of any defective or void tax certificate or tax deed made or issued by any such county shall be commenced or presented during the life of such tax certificates on which such deed was issued in accordance with the limitations as provided in s. 75.20; and whenever an action relating to the validity of a tax certificate or tax deed shall have been commenced within the time above limited and a final judgment shall not be rendered in such action until after the expiration of the time so limited, in such case an action may be commenced or claim presented on account of such certificate or deed within one year after final judgment declaring the same void.
Wis. Stat. § 75.24