Myojin of Towering Might has at least one indestructible counter on it.
Steps
At the beginning of your end step, Atraxa triggers, putting an indestructible counter on Myojin.
Activate Myojin by removing an indestructible counter from it, putting five +1/+1 counters on Sage of Hours and the remaining three +1/+1 counters on any creature(s) you control.
Activate Sage of Hours by removing all +1/+1 counters from it, causing you to take an extra turn after this one.