Psychonauts in the Rhombus of Ruin

The story picks up immediately after the ending of Psychonauts, with new Psychonaut cadet Razputin "Raz" Aquato joining fellow cadet Lili Zanotto and agents Sasha Nein, Milla Vodello, and Morceau Oleander in rescuing Lili's captured father Truman, the Grand Head of the Psychonauts. Using his Clairvoyance ability, Raz discovers Truman is being held at an abandoned Psychonaut research facility in an oceanic region known as the Rhombus of Ruin (a play on the Bermuda Triangle), built to study a large underwater deposit of Psilirium (a fictional element variant of Psitanium that can distort psychic powers and creates illusions). The team travels into the Rhombus of Ruin, but the jet crashes before they can act.
Raz awakens tied to a chair in the chamber Truman is being kept. Using his psychic abilities to explore the junk-filled ocean, Raz finds Sasha, Milla, Lili and Morceau trapped in Psilirium-induced hallucinations. After freeing his team from their hallucinations, Raz is pulled back into the chamber by Truman's captor, the insane ex-dentist Dr. Loboto, who kidnapped Truman on the orders of a new client. By using a Psycho-Portal given to him by Morceau, Raz enters Loboto's mind. There, he fights a gigantic version of Loboto and enters his memories, where Raz learns Loboto was once a psychic himself, and his parents disapproved of his abilities and had him lobotomized. The process removed his psychic powers and drove Loboto insane, leading to his commitment at the Thorney Towers asylum.
After Raz exits Loboto's mind, Loboto seems to have a change of heart by releasing his team, but instead leaves Raz and the others and floods the base, which they barely escape from with Truman in tow. The game ends with the team flying back to their Motherlobe headquarters as Lili tells her father about their adventures, shocking him with the revelation that Raz is her boyfriend. Unbeknownst to the others, Loboto secretly hides himself in the jet's luggage compartment.