This challenge gives us a .pcap file with the description telling us that the flag is hiding inside of it. Just like in the Eavesdrop challenge, I started out by opening the pcap file in Wireshark to a very ugly sight: 1510 packets of mostly FTP and TCP data.
My intuition for this challenge was to search the frame for picoCTF in case the flag is written in plaintext within one of the packets, so I used the filter: frame contains "picoCTF" to check for this.
With this result, I found the flag in plaintext located within the binary of the packet, which after some light formatting would reveal the flag: picoCTF{P64P_4N4L7S1S_SU55355FUL_31010c46}