Here is a possible concise summary of the text:
Two brothers, Ujjal and Souvik, are involved in a supernatural saga of the Naagmani, a powerful gem that belongs to the serpents. Ujjal is the reincarnation of Naageshwar, a saint who protected the Naagmani in his previous life. Souvik is the reincarnation of Rudraksha, a prince of the serpent dynasty who was friends with Ujjal. Sundari, a shape-shifting serpent, is obsessed with the Naagmani and tries to seduce Ujjal to get it. She also has a dark past with him, as she betrayed his love and killed him in his previous life. Kanishka, another serpent, is in love with Sundari and helps her in her mission. He also helps Souvik remember his past life and warns him about Sundari's evil plans. Sundari manages to get the Naagmani from Ujjal's stomach, where it was hidden, but she has to perform a ritual to activate its powers. Ujjal and Souvik try to stop her with the help of Kanishka and Naageshwar's blessings. Kanishka sacrifices his life for Sundari, but she still refuses to give up the Naagmani. Ujjal tricks her into touching the gem, which takes her life away as she wished for it. Ujjal and Souvik return the Naagmani to Lord Shiva and honor Kanishka's memory. They wonder what other adventures await them in the future.
Here are the key facts extracted from the text:
1. The text is a transcript of a video series called "Naagmani" which is about a mystical stone that grants powers to shape-shifting serpents.
2. The main characters are Ujjal and Souvik, who are brothers and reincarnations of Kanishka and Rudraksha, who were friends and protectors of the Naagmani in their past lives.
3. Sundari is a female serpent who is obsessed with the Naagmani and tries to kill Ujjal and Souvik to get it.
4. Kanishka sacrifices his life to save Sundari from Ujjal's attack, but she still tries to get the Naagmani from Souvik.
5. Souvik tricks Sundari into touching the Naagmani, which takes her life away as she wished for it.
6. Ujjal and Souvik return the Naagmani to Lord Shiva, who is the supreme deity of the serpents.