Idaho Code § 67-422
In the event of an attack, the governor shall call the legislature into session as soon as practicable, and in any case within ninety (90) days following the inception of the attack. If the governor fails to issue such call, the legislature shall, on the ninetieth day from the date of inception of the attack, automatically convene at the place where the governor then has his office. Each legislator and each emergency interim successor, unless he is certain that the legislator to whose powers and duties he is designated to succeed or any emergency interim successor higher in order of succession will not be available [unavailable], shall proceed to the place of session as expeditiously as practicable. At such session or at any session in operation at the inception of the attack, and at subsequent sessions, limitations on the length of session and on the subjects which may be acted upon shall be suspended.
Idaho Code § 67-422