Undertow is the twelfth episode of Slugterra. It aired on October 30, 2012.
After a wild ride on the mysterious Flumes, the Underriver that runs beneath all the Slugterra, the Shane gang find themselves dropped into a sea cavern, where they are promptly shanghaied into the crew of the Pirate Captain Malvolio Drake!
While the gang is running away from some of Blakk's men after destroying Blakk's Refinery, they escape into the mystifying Flumes, a river that runs under Slugterra. Kord shows them how to use their Mecha Beasts to run on water, and reveals that he absolutely hates the stuff, and only takes a shower once a year; under some persuading. The chase continues until finally everyone ducks into a side tunnel, where Blakk's men refuse to follow. They laugh and ride off, puzzling Eli, who realizes that they are about to fall off of a waterfall. They soon find themselves in Undertow Cavern, which is a sea cavern that's run by a reptilian pirate captain, Malvolio Drake, who gives the gang a choice to either give up some of their slugs or turn back, but the gang refuses and try to escape, but the pirates out smart the gang and capture them and put them to work for Drake. Soon however a Blakk industry's ship encounters drakes and an all out battle occurs. Whilst this happens the gang are able to escape and take over the Blakk industry's ship. Eli however ends up dueling Marvolio and his Mimkey. Eventually the gang get away on their mechas while also saving the captured Slugs by setting them free.
Sam Vincent: Eli, Guard
Andrew Francis: Kord, Pirate 2,
Lee Tockar: Pronto, Watts, Fang
Shannon-Chan Kent: Trixie
Michael Dobson: Drake, Pirate 1
- The running gag in this episode is when the Shane Gang thought the bad things are over, something worse will come and put them in danger.