Cicely's summer job--helping out at Cousin Millicent's beachside mansion--is interrupted by a mystery involving spies and counterspies. Millicent has half a dozen guests, including Lummie, who jilted her years ago at the time of her grandfather's mysterious death. Cicely and friend Greg rediscover the telescope that fits into ""Odin's Eye,"" a vantage point that had been used by the grandfather, a retired admiral, and with it view Lummie, apparently making an illicit nighttime delivery. Thereafter, the intricate plot involves most of the many characters and several suspenseful moments, including a climactic entrapment in an abandoned windmill, before the truly wicked are brought to justice, the apparently wicked are revealed as true, and Greg and Cicely have their first clinch. Odin's Eye has major weaknesses. Like Murray's A Peaceable Warrior, it's melodramatic and full of unlikely coincidences and behavior. On the other hand, Murray is adept at individualizing even minor characters with a few well-chosen phrases; many of her descriptions are apt; and in spite of its creaky machinery, her story's suspense should hold readers.