Centuries ago, humanity have been incorporated into an alien hive mind, spread by a bacterial-like infection. The "bacteria" infects the blood and brain and allows the infected to join their minds together, there is no alien overlord, just an interplanetary community of spirit. Everyone is happy.
The problem is that our immune system starts to fight back. More and more babies are born with little to no space-bacteria in their brain, and need daily injections to stay "normal".
Even worse, the space-bacteria signal strength is globally diminishing.
We can barely feel the presence of the other infected species outside the solar system, soon we'll only be able to share our thoughs with the people in our immediate vicinity.
Teams of space-travelers are send to other planetary systems in hope to find new strains of the bacteria to re-infect everyone. They are humanity last hope to be happy again.
My story explores two facets of this terrible, terrible situation:
One part is about people who stayed on earth. They are trying to find a cure against our immune system, struggle to maintain social order and try to cope with the loss of happiness.
The other is about a team send to space, they travel around, meet infected and non-infected civilizations, ask for information on the bacteria in space-taverns, learn the concept of money and hire a few space-mercenaries to help them in their noble quest.
I have problems with the "cultural exchange" aspect of the intergalactic quest:
Can hive-people communicate effectively with non-hive people?
We'll assume they have a language-to-language translator-machine, the problem is they directly shared their thoughts with trillions of creatures all their lives, do they even have the ability to translate concepts into sentences?
How can they convince space-mercenaries to help them find the happiness-bacteria? I assume no non-hive people will want to approach the thing, so they'll have to understand the way a non-infected person think and to find strong arguments.
In the everyday aspect of the mission, can connected humans and autonomous personalities live together in the same ship and interact without too much misunderstandings and fights? What will the cohabitation be like?
Side note: Please tell me if any aspect of this story is badly-explained, or contradictory, or even if you already saw the exact same thing elsewhere (I think the story is original but I haven't done any research).