It is not a new coin/blockchain. It is software that allows to broadcast a multisig bitcoin transaction (creating a channel) with another peer, and then the bitcoin locked there can move as in a pipe, back and forth with very low or null fees, and by smart contract you can close the channel unilaterally by broadcasting another transaction that will redeem onchain your latest balance in the channel. What is interesting is that you can hop/multihop on peers, so it's a network which utility grows exponentially with the numbers of participants. Like an Internet of money.