The twelfth episode of season 2 sees Castle reunited with 'the one that got away' during an investigation of a murder case.
Alyssa Milano's wedding day turns sour when the body of a bridesmaid is found in her closet. Milano guest stars in the January 11 episode of "Castle" as the former flame of Castle who makes Beckett a little jealous.
When Castle and Beckett are called to a wedding to investigate the death of a bridesmaid, Castle is stunned to discover that the soon-to-be bride is his old flame, Kyra, "the one that got away". Complications ensue as Kyra, caught off-guard by Castle's reappearance in her life, wonders if she's marrying the right guy.
With the nuptials forestalled and the entire wedding party under suspicion, Beckett questions Castle's ability to be objective about the case. But when it looks to Beckett like Castle and Kyra might rekindle their romance, her judgment may be compromised as well.