This movie is based on Surah 18 (Al-Kahf) of the Holy Quran, covering almost every thing about the Ashab-e-Kahf (The Dwellers/Men/Companions of the Cave).
It was Allah's will for them to go and take shelter in the cave, and save them from the persecuting Romans.
They did not turn back and think about their families, and Allah made the cave so secure that no one was able to get into the cave and harm the sleeping followers for around 300 years, after which they woke up.

Watch this movie and understand Surah 18 (Al-Kahf) of the Holy Quran in a much better way. It teaches us to be steadfast & firm in our belief of Allah.
This is in Urdu with English Subtitles