Saheeli triggers, creating a 1/1 Servo artifact creature token.
Resolve Temporal Mastery, causing you to take an extra turn after this one and exile it.
Activate Contagion Engine by paying ({6} magic symbol) and tapping it, putting two loyalty counters on Saheeli.
Activate Saheeli by removing two loyalty counters from it, causing the Servo to become a copy of Mirror of Fate until end of turn.
Activate the Servo by tapping and sacrificing it, choosing Temporal Mastery and up to six other cards face up in exile, then exiling your library and putting the chosen cards on top of your library, with Temporal Mastery being the top most card.
Move to your next turn, drawing Temporal Mastery during your draw step.