It seems you're referring to the classic TV series Hatim (often the 2003-2004 DD National version or the later 2013 StarPlus adaptation), based on the tales of the legendary Arab hero Hatim al-Tai. Since "Episode 6" can vary slightly depending on which version you're watching, I'll provide a complete, detailed story summary of the most common narrative for Episode 6 in the popular Hatim (2003) series.
They soon find a surviving old woman, half-mad with grief. She tells them the village was once prosperous under the rule of , a kind and just ruler. But years ago, a rejected suitor — a powerful dark magician named Kaaldev — cursed her. He cast the “Nidra Pash” (Sleep Noose), causing the princess to fall into an enchanted sleep. The curse spread from her palace to the entire kingdom, freezing everyone in slumber.
Kaaldev’s condition: The curse can only be broken if a prince of pure heart retrieves the from the Cave of Echoes and places it on the princess’s forehead. But anyone who enters the cave hears their deepest fear echoed back so loudly that they go mad and never return. Hatim’s Challenge Hatim volunteers to break the curse, not because it’s one of the seven riddles, but because it’s his nature to help. Bahadur tries to dissuade him, but Hatim insists.