Close the book on something
Definition 1 of 1
Pro Tip 1/3Finality Implied
Use the phrase to convey a sense of definitive completion or conclusion. 
With the last episode aired, we can close the book on our favorite TV series.
Pro Tip 2/3Emotional Weight
The phrase often bears emotional significance, signaling moving on from something substantial. 
She closed the book on her past regrets and looked toward the future.
Pro Tip 3/3No Reopening
Suggests there's no intention to revisit or restart what's being ended. 
After the settlement, he closed the book on the long legal battle.