著名的关原一战，奠定了德川家族两百多年幕府的胜局。为了让身为浪人的丈夫稻叶正成（原田大二郎 饰）谋得职位，逆臣之女阿福（十朱幸代 饰）亲自拜谒伏见城，更被迫委身好色的德川家康（若山富三郎 饰）。次年，阿福产下一子，但和丈夫的关系已无可挽回。适逢家康之子秀忠（金田賢一 饰）的正室阿江（吉川十和子 饰）临产，阿福带着孩子赶赴江户应征乳母。十月怀胎，一朝分娩，然而阿江最终产下一名死婴。为免引起后宫动乱，大年寄大姥（草笛光子 饰）暗自将阿福的孩子与死婴对调，并命名为竹千代。转眼时光飞逝，竹千代渐渐长大，阿江也再次产下健康的男孩国松，围绕将军继承人的纷争把所有人都卷入这个巨大的漩涡之中……

The rise to power of the famed Lady Kasuga no Tsubone, who established the 'Ooku' (the women's quarters at Edo castle) and acted as nursemaid to Tokugawa Iemitsu, the future 3rd Shogun is chronicled in this historical drama. Intrigue and suspicion abound as the two brothers Iemitsu and Tadanaga vie for the post of Shogun, while behind the scenes the remnants of the defeated Toyotomi faction, lead by Lord Ishida Mitsunari attempt to discredit the Tokugawa Shogunate and regain their former position as rulers of the nation. The hidden battles between Shogun Hidetada's wife and mistresses of the 'Ooku' come to light as they force the two brothers into a life or death struggle.