The beloved Professor Thornton McHattie has recently died.  In his last days he added challenges into his final will and testament over which the others compete.  While finishing the second challenge, to sail along the Woptecasni Horizon, the boundary in the middle of a very large lake where the sight of land disappears all around, the boat runs aground on a sandbar that occasionally appears in the middle of it.  Their efforts to get off the sandbar and to close McHattie’s conditions drive them to confront his residual power over them, and the transactional reality of his generosity.