The Engine runs on a cycle. What actually happens can be very complicated, but here is a more thorough (though still simplified) explanation of the process that the Engine uses.
Top of Cycle:
Advance the clock by one Moment.
Set the clock Hours and Days
Check to see if nothing has happened for at least 10 Moments;
if so, terminate the story.
Check the clock time; if it's time to do so, trigger the ClockAlarm.
For each and every Actor, starting with Fate, do the following: (LOOP)
Relax the Actor's moods (let them relapse towards normalcy)
For each and every one of the Actor's Plans, do the following: (LOOP)
Check that the Plan's Execution Time has elapsed.
Check that the Actor is on the same Stage as the Plan's DirObject;
if not, skip this Plan.
Check the Audience requirement for the Plan's Verb;
if the Audience requirement is satisfied by the situation, then proceed;
otherwise, skip this Plan.
Check for an Abort Script for this Verb; if there is one, execute it;
if it returns "true," then abort executing this Plan and throw it away.
If we've gotten this far without skipping this Plan, then execute it:
store the Plan into the HistoryBook as an Event.
execute any Consequence Scripts for this Event
if this Verb is "depart for," do some special things to remove the Subject
from his current Stage.
if this Verb is "arrive at," do some special things to place the Subject at his
Have Fate react to the Event.
based on the Audience requirement for the Verb, decide who on the Stage
actually witnesses the Event.
Have each witness in turn react to the Event.
Have the DirObject react to the Event
Have the Subject react to the Event.
Throw away the Plan.
Do not execute any more Plans for this Actor (unless the Actor is Fate).
End of Plans loop
Did the Actor execute any Plans? If so, then proceed to the next Actor. If not, do this:
Consider whether to go to another Stage:
Does the Actor have a previously defined TargetStage? If so, go there.
If not, sort through the Plans and find the most important Plan.
If there is one, go to the Stage where the planned DirObject is
(so we can execute the Plan on the DirObject).
If the Subject can't do that, then pick a new Stage to go to based on:
how long the Actor has been sitting around at the current location.
how Unwelcoming_Homey another Stage is for this Actor
End of Actor loop
End of main loop—go back to the top of the loop
If it's time to terminate the story, set a Plan for Fate to execute "Fate penultimate verb Protagonist." This system Verb will then lead to the very last Event, "Fate happily ever after Protagonist how much." You, the author, may insert intervening Verbs between penultimate verb and happily ever after; however, if you do so, see the cautionary notes in System Verbs.
You may also write WordSocket scripts for the Quantifier in the very last sentence, "Fate happily ever after You this much: [Quantifier]," to reflect how well or poorly your player did. If you wish, however, you can just leave this at its default setting of "medium," or you can remove the Quantifier. To remove the happily ever after Quantifier, go to System Verbs: happily ever after: Properties and eliminate 4Quantifier from the list of WordSockets.