Idaho Code § 43-726
Every action, suit or proceeding which may be commenced for the purpose of determining the validity of a tax deed, brought by the original owner of the land or his assigns against the grantee named in the tax deed or his assigns, or to quiet title against him or them, or to remove the cloud of the tax deed, or to recover the possession from the tax deed grantee in possession, in cases where the assessment for which the land was sold had been paid before the issuance of the tax deed or the land redeemed after the issuance of the tax deed, or the lands were not subject to taxation at the time of assessment shall be commenced within two (2) years from the date of the issuance of the tax deed; and in every such action, suit or proceeding, whether before or after the issuance of tax deed, the party claiming to be the owner as against the district or against a party claiming under the tax certificate or under the tax deed shall tender with the first pleading in such action, suit or proceeding, and pay into court at the time of filing the same, the amount of the purchase price for which such lands were sold, or the amount of the assessment, penalties and interest for which a tax deed was issued to the district, together with all taxes and assessments which have been paid by the purchaser or paid or assessed by the district on said land after issuance of the tax deed, together with interest thereon at the rate of ten per cent (10%) per annum from the respective time of payment of such sums up to the time of filing of such pleading, the same, or such portion thereof as the court shall find to be just, to be paid to the district or said purchaser, his heirs or assigns, in case the right or title of the district or said purchaser shall fail in such suit, action or proceeding.
Idaho Code § 43-726