In the second season, Halime tells Ertuğrul that she’s pregnant. Immediately after that Ertuğrul is captured by the Mongols, led by Bayju Noyan. Meanwhile, the Kayi Tribe led by Hayme Ana seeks refuge with the Dodurga tribe, led by Korkut Bey, her brother. They were attacked by Mongols and there were many casualties. When the Kayis go in search for Ertugrul, they find his ring in a pile of burnt coal and assume that he is dead. Halime is devastated and nearly loses her baby, but is revived when Ertuğrul returns in time. 

Ertuğrul’s escape from the Mongols and subsequent return to his tribe creates internal strife between him and his cousin Tugtekin, the head alp of the Dodurga. As Noyan had nailed his hand, he was incapable of holding a sword. Thus, his head of alp title is taken away from him and he is neither an alp nor a head. Meanwhile, Aytolun (Hayme Ana’s sister in law – Korkut Bey’s second wife), plots behind his back to help her brother Gümüstekin become the margrave with the help of Emir Sadettin Kopek. Ertuğrul is sent on exile by Hayme Ana. Tugtekin confronts him but Ertuğrul tells Tugtekin that his alp Kocabash is a traitor and the Mongols would be arriving. As soon as Ertuğrul leaves, Kocabash changes sides and Noyan and his soldiers injure Tugtekin badly and presume him to be dead. Kocabash goes to the nomad camp and tells everyone that Ertuğrul killed Tugtekin. Ertuğrul chops his head as a punishment when he arrives at the nomad camp. Korkut throws a knife at him which pierces Hayme Ana. On the execution of Ertuğrul his Alps save him and Tugtekin appears which makes the situation better. Head of Alps is taken back from Tugtekin and given to Gundogdu. Gokce gets married to Tugtekin. The tension is further escalated with the arrival of Sungurtekin, Ertuğrul’s long lost brother. Aytolun and Goncagul steal the Oghuz seal from Sungurtekin. Aytolun poisons Korkut and herself and puts the blame on Banu Cicek, Korkut’s adoptive daughter. However Ertuğrul shows Gundogdu And Hayme Ana her reality and stops Gundogdu from marrying Goncagul. They go to war secretly with Gümüstekin, Aytolun And Goncagul follow Selcan and Halime to the stream bed. After a fierce fight, Aytolun takes advantage of Halime’s pregnancy and knee’s her on her womb. Halime faints and Aytolun attempts to chop her head off but is killed by an arrow shot by Abdurrahman alp. Goncagul runs away. Noyan and Goncagul fall in love and kidnap Gokce from the nomad tent who kills Goncagul. Noyan later kills both Gokce and Tugtekin. Ertuğrul’s son, Gündüz is born. Turgut stomps off angry because Ertuğrul does not let him kill Noyan and take his revenge. Ertugrul mortally wounds(he reappears in Season 4) Noyan who attempts to kill Gündüz. After defeating Gümüstekin and Noyan, the tribe is split between joining Ertuğrul on the Western border of Anatolia, or staying with Gundogdu and Sungurtekin. Moreover, till that time Ertuğrul’s cousin Tugtekin are dead. In the end, Ertuğrul, his brother Dundar, Halime Sultan, Gunduz, and Hayme Ana, along with 400 other people journey to the western edge of Anatolia, leaving behind the rest of the Kayi Tribe. Sadattein Kopek’s soldiers attack them and kill Yigit Alp. Bogac tries to kill Gündüz, but is killed by Turgut, who rescues Gündüz and is made head of Alps by Ertugrul. They migrate to a new fertile land near the Byzantine-Seljuk border.