Episode 16 Amba, Ambika, Ambalika, and a Kingdom without a King
Two weddings, a Funeral, and a Kingdom without a King: Bhisma returns to Hastinapura with the 3 Kasi princesses, and the marriage of Ambika and Ambalika to Satyavati's son, Vicitravirya.
References:
Bhisma recounts Brhaspati’s rape of Mamata, and the story of Dirghatamas (I.98.8-31)