Quarantine.During a heatwave, several ships are quarantined at sea to prevent the risk of spreading infectious disease. O.J., the oldest Tug in Bigg City Port, is having trouble with his engine and a near-miss with the coastguard's messenger causes his fire barge to collide with the Fultan Ferry, causing it to sink with its cargo on board. Captain Star is being pressured by Burke and Blair to sell O.J. for scrap and must make a decision soon. Meanwhile, Sunshine has been ordered to bring in the tramper Nantucket, but has his doubts when he sees its quarantine flags being lowered without authority, so he heads back to port...