Now, I have read "The Boys" from start to finish, so this episode was particularly up my street, inspired as it was by both the art style and the tone of those books.
Butcher (Jason Isaacs) calls in on OD (Kieran Culkin), drug dealer to the superheroes and threatens to kill him unless he spikes the drugs of Great Wide Wonder (Michael Cera), a high-profile hero but not one of the seven. OD reluctantly complies, but nobody could have predicted just how horrific the outcome of their actions turns out to be.
Interesting mix of voice actors for this one. Simon Pegg finally gets to play Hughie, the character he inspired. Jason Isaacs gets to play Butcher, in a performance that is much nearer to the voice that I heard reading the comics all those years ago, than Karl Urban's (not that I dislike Urban's performance, but a convincing English accent, it is not). Anthony Starr and Dominique McElligott reprise their roles as Homelander and Queen Maeve though.
The real selling point though is that animation style made to directly mirror the original look of "The Boys" graphic novels and is a story written by Garth Ennis himself. It's apparently supposed to be taking and canonically happening in the comics universe (pretty early in it, based on context) but it's a fairly short, standalone addition, as typically gory, violent and course as you might expect. Definitely entertaining though and a good addition to this series.