Thiaf is a prequel to the series. It teaches us about how Garrett became a thief so we take control of him when he was 14 (hence the game title spelling - to make the game's theme closer to the modern Thief fanbase)
There is an awesome action sequence where Garrett, whose parents were killed by an evil duke for no reason (but Garrett sweared he will get his revenge) has to steal a ring from duke's captain of the guard.
When player faces the captain after following quest compass through 2 branching parallel corridors Garrett demands the ring, but the captain refuses and starts to run away.
Player than presses A when prompted - young Garrett makes a jump to the balcony overhead, pushing away from the balcony, getting his stylish knife out and flying towards the captain.
In a slo mo the captain turns around, gets his sword out and blocks Garrett's attack. This is where player needs to quickly and repeatedly press Y as they struggle to come out of the block.
Eventually young Garrett breaks the block and the prompt to pull left stick clockwise appears. In a similar move Garret drives the knife through the left kidney of the captain, takes the ring off of his finger and disappears into the night, leaving the dying captain in a pool of blood.
ACHIEVEMENT UNLOCKED: STOLEN THE RING