The Depths of Cousin Fethry is a cartoon story written by Christian Magalhaes (alongside DuckTales 2017’s usual team of writers), and directed by Matthew Humphreys. Taking place in the 2017 Continuum, it features Scrooge McDuck, Huey, Dewey, Launchpad McQuack, Donald Duck, and, in their debut, Fethry Duck, Oceanika, Fethry's Team and Mitzy.
Huey and Dewey travel to the McDuck Sublab, an underwater facility belonging to Scrooge McDuck, to meet Donald's cousin Fethry Duck. Another crazy adventure begins as Fethry turns out to be eccentric to the point of insanity, the McDuck Sublab derelict and useless, and the water roamed by mutant monstrosities…
Behind the scenes
The second episode of Season 2 of DuckTales 2017, The Depths of Cousin Fethry was released in October of 2018.