Complex sentence: Professor Andrew Patterson (Glenn Ford) returns to his "alma mater", the College of St. George in San Francisco, for the initiation of a new member into a secret society, the Brotherhood of the Bell.
Split into simpler sentences: Professor Andrew Patterson (Glenn Ford) returns to his "alma mater", the College of St. George in San Francisco. He is attending the initiation of a new member into a secret society, the Brotherhood of the Bell.