This lair features in various TMNT stories that take place during the turtles' earlier lives (such as Not Forgotten), but it must be abandoned after volume 1 issue 2 when it is discovered and partially destroyed by Baxter Stockman's Mousers. The turtles are given a new home in April O'Neil's apartment in the Second Time Around building, and Splinter joins them later after the destruction of TCRI. In this lair, Leatherhead gradually tries to construct a transmat device in the hopes of eventually rejoining his adoptive Utrom family on their homeworld.