Complex sentence: After the success of "3 Idiots", director Rajkumar Hirani and writer Abhijat Joshi started work for next project, they had written a story about a character who had the ability to get into another person's mind to make that person a better human being.
Split into simpler sentences: After the success of "3 Idiots", director Rajkumar Hirani and writer Abhijat Joshi started work for next project. They had written a story about a character who had the ability to get into another person's mind to make that person a better human being.