Twin Cities indie-rap hero P.O.S. has not issued a new recording under his solo moniker in more than three years, so it's no surprise that his first track back is a doozy.

The Doomtree star and Rhymesayers alumnus finally debuted a new and clearly quite pent-up tune this morning called "Sleepdrone/Superposition," which clocks in at nearly nine minutes, covers a lot of lyrical territory and includes eight different guest collaborators, including Lizzo, Astronautalis, Allan Kingdom and Bikini Kill punk icon Kathleen Hannah.

The song was specifically timed to Monday morning to coincide with the two-year anniversary of P.O.S.'s kidney transplant. It is available for download via iTunes.

"I tried to write a note to everyone that came out and supported when my kindey couldn't clean up my poisonous blood," the real-life Stef Alexander spews three minutes into the sonic bruiser of a tune. "But I just stared at the page / And when I wrote it I felt nothing but the numbing of cliché."

In an interview a week ago as he prepared the final mix of the song (posted below), Alexander said those lyrics point to the false starts and hesitations he had after his kidney transplant trying to get back into the P.O.S. musical mindset again.

"It seemed like everything I was writing in the months after my transplant was totally opaque, health-related depression rap," he said, "which was good for me in the cathartic sense but wouldn't have been good music in the entertaining sense."

Thus, last year's outing behind Doomtree's third all-crew album, "All Hands," probably couldn't have come at a better time. "It really helped me ease back into performing, having those five or six other people with me on stage," he said. "It helped me build up my endurance, and to find my voice again."

He enlisted a lot of his closest allies plus one "dream collaborator" to help him voice the grand ideas in "Sleepdrone/Superposition," which is based on a quantum theory about the unexamined state of objects. P.O.S. summed up his idea of superposition as "trying to be still and moving at the same time, trying to calm down and live a peaceful life but also still go hard as an artist." The song also includes lyrics about raising his two sons and trying to "make my mama so [bleepin'] proud of me."

Alexander's older son, Jacob (now 16), makes his recording debut on the song under the moniker Hard R. Said Stef, "I wouldn't have wanted him on it if he didn't already have his own flourishing sound." As for Kathleen Hannah, who can be heard muttering, "You're supposed to be happy to be alive," he said he reached out to her on a hopeful whim: "We heard back from her pretty quickly, and she was into it, thankfully."

While it's not clear if "Sleepdrone/Supersposition" will wind up on an album, Alexander said the song can at least be seen as the first step toward the next P.O.S. record, which he hopes to have out by year's end. It would be his first record for Doomtree's own in-house label after three albums for Rhymesayers.

"I think I have a good start to a record, a lot of songs in the zone but not quite all the way there yet," he said.

There's plenty here in this song to mull over in the meantime.