抽丝剥茧

1. • to unwind the silk thread from the cocoon (idiom)

     lit.

2. • to unravel a mystery to painstakingly follow the clues to eventually get to the bottom of the matter

     fig.

Character by character

• 抽(chōu)draw out
• 丝(sī)silk
• 剥(bō)peel
• 茧(jiǎn)cocoon