NBC has released the official description of Grimm season 3 episode 19 "Nobody Knows the Trubel I've Seen". This episode is slated to air on Friday, April 25 at 9/8c.

A LETHAL NEW PRESENCE COMES TO PORTLAND –

JACQUELINE TOBONI, C. THOMAS HOWELL AND ALEXIS DENISOF GUEST STAR --

• Nick (David Giuntoli) and Hank (Russell Hornsby) investigate a dangerous female suspect (guest star Jacqueline Toboni) leaving a trail of Wesen in her wake.
• Elsewhere, Adalind (Claire Coffee) takes measures into her own hands, even if that means forging a dangerous alliance.

Bitsie Tulloch, Silas Weir Mitchell, Sasha Roiz, Reggie Lee and Bree Turner also star. Philip Anthony Rodriguez also guest stars.

Source: NBC