Alex tells Horatio that Lauren suffered from acute renal failure and believes she was murdered. Eric says Ethan was going to propose to Lauren that day. Eric figures since Ethan was shifty, he was lying to him.

Walter and Calleigh search Lauren's apartment for poison, but don't find any. Ethan tells Eric he brought Lauren food every day that week. He says she started to get sick after they went to a restaurant. Eric informs him that Lauren was poisoned. Ethan starts to cough, says he didn't kill Lauren, then tries to run. Eric tackles him and handcuffs him, but he does not respond. He calls out for Alex to help.

The team meets to discuss the case. Eric says Lauren was poisoned by E.Coli. He reports that Alex believes it is a deadly strain. Eric explains that E.Coli has a source. Horatio says they have to treat the case just like any other murder. Eric goes to Ethan's room and digs in his wallet. He finds a receipt for a restaurant called Sambellos.

Calleigh goes to Sambellos and asks a chef about Lauren. The chef says they have a clean health inspection report. She explains E.Coli comes from the grower.