Complete story — includes the ending
A man celebrating his 21st birthday is found walking in the street, covered in blood and attacking cars with an axe. The CSIs find four bodies (two of them the man's friends, the others two unknown girls) in the man's hotel room, but soon they prove that the man (who is suffering from LSD-based hallucinations) is innocent. The team must retrace the man's steps through the night so they can find the killer. In the end they find that the girls (who were the ones that dosed the man with LSD) worked for a drug lord and wanted to leave, with the man and his friends meeting them as the girls escaped: the drug lord killed the four victims, which the man witnessed - and Mac ends up saving him when the drug lord tries to kill him.
Sources and content license
Source and revision history · Adapted from Wikipedia contributors, CSI: NY season 6. HTML formatting and reference markers removed. · Content license