Step 1: State its origin:
After World War I, the victorious Allies threatened to dismantle the Ottoman Empire and strip the Ottoman Sultan of his position as Khalifa (spiritual head of Sunni Muslims) through the Treaty of Sevres (1920).
Step 2: State its Indian leadership and aim:
Indian Muslims, led by the Ali brothers (Maulana Muhammad Ali and Shaukat Ali) and supported by Maulana Abul Kalam Azad, launched the Khilafat Movement (1919-1924) to pressure the British government to preserve the Khalifa's authority and the integrity of Muslim holy places.
Step 3: State its link with the wider freedom struggle:
Mahatma Gandhi supported the Khilafat cause and merged it with the Non-Cooperation Movement (1920-22), seeing it as an opportunity to unite Hindus and Muslims in a joint struggle against British rule.
Step 4: State its end:
The movement declined after Mustafa Kemal Ataturk abolished the Caliphate itself in Turkey in 1924, removing its original cause.
Final Answer:
\[ \boxed{\text{A 1919-24 pan-Islamic movement by Indian Muslims to protect the Ottoman Caliphate, merged by Gandhi with the Non-Cooperation Movement}} \]