A brother and sister's battle over a prized heirloom piano unleashes haunting truths about how the past is perceived — and who defines a family legacy.

第10季将引入另一条长期故事线——意即引入一个和第八季「复制者」（The Replicator）类似的「未知对象」（unsub）。詹妮弗·洛芙·休伊特从本季开始扮演FBI探员Kate Callahan，她将填补Blake离去后留下的空白。行动分析组在调查一个连环杀人案，这个时候，一位新的探员Kate Callahan加入团队中。

Counter-terrorism agent Jack Bauer attempts to stop the assassination of United States Senator David Palmer on the day of the California presidential primary, while those spearheading the assassination plot stop at nothing to exact revenge on Bauer and Palmer.