We have a brand new exclusive clip from the brand new In Plain Sight episode Whistle Stop, which will air on Wednesday, April 21 at 10 PM ET on the USA Network. Click below for our brand new exclusive clip, which features Mary and Marshall trying to reassure a witness, which also features guest star Steven Weber, and you can take a look at the new TV spot for the episode as well.

Mary and Marshall try to help FBI Agent Mike Faber convince his informant to enter WitSec. Despite their best efforts, the informant refuses their protection and gets himself into a heap of trouble. Meanwhile, Stan has to deal with an ex-boxer/witness suffering from pugilistic dementia!

In Plain Sight stars Mary McCormack, Frederick Weller, Nichole Hiltz, Paul Ben-Victor, Lesley Ann Warren and Cristián de la Fuente. The 3.04 episode Whistle Stop will air on Wednesday, April 21 at 10 PM ET on the USA Network.