Watch this sneak peek of Grimm episode 2×04 “Quill” to see an outbreak of love and something more sinister.

This just isn’t the season for love on Grimm. Just when things are heating up for our favorite Wesen couple, Monroe and Rosalee, an outbreak of the yellow plague will come between them! While on a romantic picnic they just barely escape an infected Wesen. Then Rosalee’s life hangs in the balance when she catches the disease. Nick also comes across the disease in an investigation. Will Monroe and Nick be able to save Rosalee in time?

“Quill” will air September 3 at 10 p.m. on NBC