At the Croton Filtration Plant in the Bronx, the sandhogs continue to mine deep beneath the city. After “punching through” to the 118-year old New Croton Aqueduct tunnel, Repete and his crew prepare for the project’s next step of permanently joining the two tunnels. In the upper tunnel newly appointed foreman Anthony Aviles is pushing his mole crew too hard. Tensions build until the gang finally snaps and a fight breaks out on the mole, forcing Walking Boss Morgan Curran to take matters into his own hands. Meanwhile, in the heart of Manhattan, at the new #7 subway extension site, Walking Boss Martin Hostetter is out for the day, leaving Foreman Ryan McGinty with the greatest challenge of his career…his first solo blast.