The brothers had fallen out over a spoon. Each remained implacable on the question of its ownership, and attempts to requite years of generosity had degenerated into attempts to collect debts. (implacable: unappeasable, relentless, inflexible; requite: repay, reciprocate, return) A granddaughter had begun to resent both men for a quarrel that could outlast them. (resent: begrudge, take exception to, take offense at)
Her discovery owed more to serendipity than shrewdness. (serendipity: fortunate discovery, happy accident, lucky find; shrewdness: acumen, astuteness, sagacity) Sorting family photographs, she found both brothers holding identical spoons. With the astuteness of a child who knew her audience, she took each man a separate print. (astuteness: shrewdness, discernment, perceptiveness) There was one spoon missing, but neither had stolen the other's.
The older brother offered an abject apology. (abject: servile, submissive, groveling) The younger's magnanimity extended to tea and exactly one biscuit. (magnanimity: generosity, large-heartedness, nobility of spirit) A trace of their ancient rivalry survived, but it was much easier to live with over a shared plate.