The Mystery of the Suspicious Circle

The Mystery of the Suspicious Circles (per bell TV guide, plurally The Mystery of the Suspicious Circles on CBC's guide) is scheduled to debut 24 August 2019. It's s2e18

The plural is correct as there are more than one.

summary
http://archive.is/Y9Cud

9:23 AM Addison (HD) - Series 2 - Eps 18 - The Mystery of the Suspicious Circles When crop circles begin appearing in Ayrton Park, Alex suspects visitors from the fourth dimension, but Addison begins sleuthing in search of a different explanation.