She wants to restore an old theater that is 'falling into decay'. [=falling into ruin]
We're concerned about the 'decay' [='deterioration'] of our public school system.
Tomatoes that fall off the vine will 'decay' [='rot'] on the ground.
(..) They guard it because they have hope. A faint and fading hope that one day it will flower. That a king will come and this city will be as it once was... ...before it fell into decay. The old wisdom borne out of the West was forsaken. Kings made tombs more splendid than the houses of the living... (..)2003 The Lord of the Rings: The Return of the King