In this episode, Doctor Beverly Crusher (Gates McFadden) falls in love with Odan (Franc Luz), a Trill mediator.
Commander William Riker (Jonathan Frakes) volunteers to act as a temporary host, complicating the relationship between Crusher and Odan.
The mediation proves successful, but after Odan is transferred to a new, female Trill host (Nicole Orth-Pallavicini), Crusher chooses not to continue the relationship.
While trying to save the alien in sickbay, Dr. Crusher comes to learn that Odan is a Trill, a species which symbiotically lives within its host's body.
Dr. Crusher is puzzled and full of emotion as she later confides to Counselor Deanna Troi (Marina Sirtis) and wonders about the true depth of her feelings for Odan.
Dr. Crusher does everything she can to extend Riker's and Odan's chances while the Enterprise races to meet the Trill ship, and has a deeply emotional moment with Captain Jean-Luc Picard (Patrick Stewart).
He said that it was a valid point of view, and that McFadden's lines in the final scene made it clear that it put forward a hope that homosexuality would be better accepted in the future.
[3] The subject matter was revisited in the Star Trek: Deep Space Nine episode "Rejoined",[4] which featured one of the earliest televised lesbian kisses.
[5] The character of Odan would return in non-canon Star Trek publications, including in the short story "First Steps" within The Lives of Dax anthology.
[10] James Van Hise, in his book The Unauthorized Trek: The Complete Next Generation, called the introduction of the Trill an "element crucial" to Deep Space Nine, but was critical of the decision to have Crusher not be interested in Odan once he had transferred to his new female host.
[11] This "apparent homophobia" was said to have resulted in the episode being "widely criticized" by David Greven in his book Gender and Sexuality in Star Trek.
[12] Keith DeCandido, in his article for Tor.com, said it was difficult to give a fair review of the episode due to the Trill being explored in greater depth in Deep Space Nine, and the subsequent alterations made for that series compared to "The Host".
[13] He criticised the reaction of Crusher at the end of the episode, saying that she would "get into bed with shifty aliens with weird ridged foreheads but for some reason draws the line at space ladies".
[14] The episode was later included on the Star Trek: The Next Generation season four DVD box set, released in the United States on September 3, 2002.