History channel's 'Six,' a television drama series that chronicled the daily lives and operations of the operators who are part of the US Naval Special Warfare Development Group (DEVGRU), more commonly known as SEAL Team Six, has been canceled after its second season.

According to Deadline, the decision to ax the show, which had so far drawn reasonable reviews, has to do with the cast options expiring at the end of this week. The steadily declining ratings for the second season arguably played its part as well.

Created and written by William Broyles and David Broyles, a military special operations veteran, the premiere of the eight-episode first season in January 2017 proved to be a game-changer for History, putting it on the map with on what is currently a highly-competitive field. It subsequently earned a renewal for season 2 before the finale had even wrapped up.

However, that same factor would prove to be its downfall, with the ratings for season 2 reportedly running at almost 50% below its predecessor's average for live+same day viewings. Each of the episodes from the first season had drawn in close to 1.5 million US viewers, while its follow up only managed to garner about 0.7 million. This, in turn, must have forced the executives' hands to take the call to not renew it further. 

The first reason revolved around a tightly-knit pack of SEALS — Senior Chief Special Warfare Operator Richard 'Rip' Taggart (Walton Goggins), Senior Chief Special Warfare Operator Joe 'Bear' Graves (Barry Sloane), Chief Special Warfare Operator Alex Caulder (Kyle Schmid), Senior Chief Special Warfare Operator Ricky 'Buddha' Ortiz (Juan Pablo Raba), Chief Special Warfare Operator Armin 'Fishbait' Khan (Jaylen Moore), Special Warfare Operator First Class Robert Chase (Edwin Hodge), and Special Warfare Operator First Class Beauregard 'Buck' Buckley (Danny Boaz) — working to track and bring down Emir Hatim Al-Muttaqi (Jarreth J Merz) and Michael Nasry (Dominic Adams).

Season 2 saw the addition of Special Warfare Operator First Class Trevor Wozniak (Eric Ladin), Gina Cline (Olivia Munn), as well as a new villainous mastermind, Tamerlin 'The Prince' Shishioni (Nikolai Nikolaeff), and saw Graves take over as the defacto new leader of the squad after Rip's death.

They must work together with the CIA and pool their collective intellects to track and stop Shishon as he wreaks havoc across eastern Europe. When the chase leads them to the border of Russia, their actions could possibly set forth a domino effect that leads to World War III.

Season 2 of the show began airing this past May 28, with its sixth episode 'Indian Country,' having premiered on Wednesday. The cancelation will not affect its current season, with the last three episodes — 'FUBAR,' 'Scorpions in a Bottle,' and 'The Reckoning' — set to run as scheduled.