What is the main conflict in The Book and the Brotherhood by Iris Murdoch?

The Book and the Brotherhood is an intricate novel about a group of middle- aged Oxford graduates. Almost three decades earlier, they form a group known as the Brotherhood. Its sole objective is the financial support of a fellow graduate, David Crimond, so that he can continue his work writing a book about his Marxist political philosophy. Now, a reunion takes place at Oxford, which the elusive and solitary Crimond also attends. Many years previously, Crimond seduced Jean Cambus, the wife of a fellow graduate, and the affair drastically changed the dynamics of the relationships within the Brotherhood. He has come to the midsummer ball for the express purpose of seducing Jean for the second time, and he succeeds in his quest. Jean leaves Duncan, setting into motion a number of unsettling events that culminate in the death of one of the Brotherhood