Inspired by Drew and Stu's boat, Tommy and Chuckie decide to sail a pretend boat of their own, with Angelica's doll Cynthia as the captain. When they accidentally lose the doll in the sewer, will Angelica ever get Cynthia back? - Description from Klasky Csupo.
While Stu and Drew are cleaning Drew's boat, Tommy and Chuckie shanghaied Cynthia so she could be captain; however, when she got lost in the sewer system, it broke Angelica's heart with foreign cry, because they played with her doll without her permission. She did get her back, but not without sailing miles and miles in the sewers and taking a bath in toxic waste. Meanwhile, after being chased away by Angelica, Spike hitches a ride in a garbage truck to the city dump, which doubles as a "scenic overlook". Angelica gots the funeral. He finds the dirty and grimy Cynthia and brings her back to Angelica. Tommy and Chuckie with Tacoma cry.
The tiltle of the episode makes a reference to the 1958 movie "The Seventh Voyage Of Sinbad" starring Kerwin Mathews.