[9] The group must deal with fuel shortage, irradiated food, hidden agendas, and other problems in their race to reach an underground military bunker.

[9] In the second season, the remaining survivors secure their path to a NATO bunker in Bulgaria, where they seek refuge from the deadly rays of the Sun.

Continuing their quest of survival with the military members in the bunker, they attempt to manage a burgeoning conflict and find a solution to the diminished supply of resources.

[10] On September 30, 2019, it was confirmed that Mehmet Kurtuluş, Astrid Whettnall, Pauline Etienne, Bebetida Sadjo, Laurent Capelluto, Alba Bellugi, Nabil Mallat, Regina Bikkinina, Vincent Londez, Jan Bijvoet, Stefano Cassetti, Ksawery Szlenkier, Yassine Fadel, Laura Sepul and Nicolas Aleshine had been cast in the series.

[3] In October 2020, Netflix announced their upcoming Turkish slate to include a submarine-set limited series, described as a "fast-paced action adventure story", starring Kıvanç Tatlıtuğ, directed by Tolga Karaçelik, and written by Atasay Koç, Cansu Çoban, Sami Berat Marçalı and Jason George.