Four Corners exclusively brings you the story of the Sharrouf children and their grandmother's epic fight to find them and bring them home to Australia.

If there was one family that represented the alarming tide of Australians flocking to the black flag of Islamic State, it was the Sharroufs.

Reporter Dylan Welch and producer Suzanne Dredge have documented the family's experience for four years, travelling with the children's grandmother as she tries to convince the authorities in Syria and Australia to release the family into her care and allow them to return home.

Across Australia the university business is booming. Higher education institutions that only a few years ago were cash strapped are now flush with billions of dollars brought in from fee paying international students.

But there are growing concerns about the consequences of the overseas student boom.

Four Corners investigates how Australia's higher education system is being undermined by a growing reliance on foreign fee-paying students.