Booth wakes up, cracking almost all the bones in his body as he answers the ring at his front door to find Brennan there. She has come to take him to get his "fitness for duty" report from Dr. Sweets. They head to his office, only to find Sweets and Daisy naked on the couch. Booth demands Sweets sign the papers, and he does so, clearly embarrassed.
The team at the lab have been charged with identifying remains from an ancient slave ship .One of the skulls has a "pink slime" on it. Turns out that is not all that's wrong with it. Brennan determines that the man has been dead for less than a month, and that he was murdered. After further investigation, they learn the victim was less than 20-years-old, and that he apparently was the victim of long-term physical abuse.
Sweets, meanwhile, complains to Booth that he finds it hard to keep his hands off Daisy, even though they are no longer together. Booth is less than sympathetic. Back at the lab, Angela creates a facial reconstruction for the victim. She runs the face through the FBI database and the victim is identified as Mike Casper. However, Casper is 28-years-old with a family. Brennan insists they have the wrong name, and Booth insists they have the right one … of course Brennan is correct. Mike Casper is very much alive; he and his wife explain he had his identity stolen, and they missed out on a house because of it.
At the lab Brennan explains that the victim had signs of repeated blows to the face between the ages of two and 14. She suggests Angela "de-age" the victim in her facial reconstruction. The new reconstruction is a match with a boy Liam, reported missing 10 years ago. Hodgins comes in and tells the gang that he now knows what the pink substance is: the bone-eating snot flower. He demonstrates how the organism works with a cannoli and a straw.
Brennan and Booth take Sweets and head to a dock where Hunter, a former friend of Liam's, works. It turns out the victim had testified against Hunter to reduce his own sentence. So Hunter has motive, and he also has a job working on a Cougar Cruise. The trio steps aboard to find older ladies dancing with younger men much to Booth's dismay, Sweets and Brennan, however, seem to get plenty of attention.
Sweets approaches Hunter, the cruise bartender, to have a heart-to-heart. Hunter admits Liam hurt him by testifying, but the two had patched up things. He explains how Liam would come on the Cougar Cruises to get money from the ladies, and that he was especially friendly with the ship's cruise director, Nadia.
Back at the lab, Hodgins has used piranha to clean the bones covered in the pink-fuzz flowers. The bones now show a series of abrasions on the skeleton, as if somebody attacked the victim with a grater. Booth and Brennan have, in the meantime, discovered a grated walkway on the ship that could have scraped the victim. They follow it to Nadia's cabin and interrupt her getting busy with a young man. Booth quickly chases the boy off and in the process sees some maggots in a nearby closet. Booth thinks Liam was killed and stashed in there until the ship got out far enough for the murderer to dump the body. Cut to Booth and Sweets interrogating Nadia, who says that if something happened to Liam she knows nothing about it. Nadia suggests they talk to Captain Kelly, the only person with a key to the maggot closet.
Kelly is brought in for questioning, but it turns out the maggots weren't feasting on human remains, only some cheese from another party. Kelly does mention he spotted the victim on deck with a woman, but he can't remember what she looks like as he was drunk. Sweets decides the only thing to do is to get the captain drunk so he'll be in the proper state to remember. Kelly gets drunk again and then remembers the woman had red hair—red hair just like the wife of Mike Casper, the man whose identity was stolen.
Claire Casper is grilled, but says she didn't kill Liam and that the team can't prove any different. She didn't figure on Hodgins, however, who has discovered the victim's bones are streaked with barnacle secretion. Hodgins and Daisy then act out their theory, Claire and Liam struggle, Claire stabs Liam with a boat hook and then Claire throws the dead man overboard and he is scraped against the barnacles. A quick check of the barnacles reveals Claire Casper's blood. Claire then admits she killed the boy after he called her a "desperate old hag." Claire cries, but Booth remains stone faced.
Later Sweets explains to Daisy that he wants them to have a substantive conversation for them to remain together. The two then reveal a shared love of Saved by the Bell and bond over that.
Camille holds a press conference revealing that the slaves have all been identified. She reads off the names on the list, but stumbles over one who shared the same first name as her great-great grandmother.