Supergirl 4x20 "Will The Real Miss Tessmacher Please Stand Up?" Season 4 Episode 20 Promo Trailer - MISS TESSMACHER RETURNS WITH A VENGEANCE — Kara (Melissa Benoist) and Lena (Katie McGrath) head to Kaznia to hunt down Lex. However, Eve Tessmacher (guest star Andrea Brooks) sets a trap for the duo that could ultimately reveal that Kara is Supergirl. Meanwhile, Alex (Chyler Leigh) gets a long-awaited phone call, James (Mehcad Brooks) practices using his powers, and Ben Lockwood (Sam Witwer) takes a dangerous stand inside the DEO. Shannon Kohli directed the episode with story by Derek Simon and teleplay by Katie Rose Rogers & Natalie Abrams (#420). Original airdate 5/5/2019.