It's 'Party of Five' run amok when the youngest member of an orphaned clan kills to keep his dysfunctional family together. The first murder occurs when they young man kills the boyfriend his sister is considering marrying. Her marriage would result in her leaving the family and that would be unacceptable. Throughout the episode, other people who pose such threats are quickly dispatched. Sam profiles the killer is someone who has felt loss and who is desperately trying to hold on to something he values. The VCTF eventually discover this decidedly unconventional family and at first, mistakenly believe the physically abusive eldest brother is the killer. Sam soon realizes, however, that there is another, more emotionally immature force at work. Bailey realizes his ex-wife is seriously involved and considering remarriage. Chloe is upset when Sam invites her new boyfriend, Paul, over for Christmas.