Season 1.
"3 years ago they came"...The Taelons offered to help humanity solve their problems and only asked that we be friends with them. They became popular with humans and some were so devoted they dedicated a church to them.
William Boone, a detective with the police department, was appointed as Director of Interspecies relations. He was recruited by the Liberation (later called the Resistance). They believed the Taelons were lying and merely wanted to subjugate humanity. Boone discovered that Da'an's Protector, Agt. Ronald Sandoval was responsible for the death of his wife. Sandoval didn't want Boone to have any distractions from his duty to the Taelons. Boone was implanted with something called a CVI (CyberViral Implant) which can give one amazing mental capabilities but also takes away your free will, this is called a Motivational Imperitive. Will's CVI was special because the M.I. was not present. When implanted, you also receive a skrill, a bio-engineered weapon. Ma'el's corpse was discovered at Strand Hill along with a message to the modern Taelons to go away. They decided not to listen and remained on Earth. The Resistance was outraged to find that the Taelons had been in contact with us for Centuries. The Taelons loved to use prisoners and others for experiments with tragic results. A Taelon subject was brought to trial under the American justice system who decided they didn't have the right to sentence Ro'haa to death so the Taelons convinced him to sacrifice himself. An alien device which had been found in an Amish community was stolen by the Taelons, who wanted to destroy it and steal the secrets it hid.
Ha'Gel, a Taelon criminal (later a Kimera) with chamelion like abilities stole bodies to mate with women and ended up killing the women. Ha'Gel stole Sandoval's body, mated with a companion protector named Siobhan Beckett and before Boone could make Ha'Gel understand that the humans did not like the Taelons anymore than he did but before he could finish, Ha'Gel was killed and Boone was gravely injured. He was placed in a tank and Zo'or, Da'an's rival, killed him. (there's more to the Da'an and Zo'or deal than meets the eye and Boone's death...nah, that's spoiling and I won't do it!)
Seasons 2, 3 and 4. (If your name is Lucky Kincaid then please do not read past this point. Liam is mentioned a lot in here.)
S2. Beckett's child grew up in a matter of minutes to become Major Liam Kincaid. He is a man with three strands of DNA and he also became Da'an's new protector when Quo'on, the enlightened leader of the Synod was killed by the Probe. Zo'or replaced him. An experiment of Dr. Belman's went awry when Sandoval either altered the liquid containing the (to be continued next editing session.)
S3. Lili's DNA was changed by Ronald Sandoval and a crackdown on the Resistance was issued by Thompson who also suspended all civil liberties. Lili goes to Jaridia and we are introduced to Renee Palmer.
S4. The Taelons are desperate and running out of core energy. Street is introduced and it is imperitive that she solve Ma'el's nine-dimensional puzzle. It is also imperitive that the Jaridians and Taelons merge to form one species again. The mothership is nuked by Hubble Urich. Sandoval is detected but Hubble says nuke it anyway, Sandoval is subhuman in Hubble's eyes and is seen as the guy who betrayed humanity.
Season 5. (If your name is Lucky Kincaid then please do not read past this point either. Liam is mentioned here too.)
Liam is lost and Renee quits her job to look for him. Street helps her. They discover they have unleashed an evil threat called (how original) the Atavus (aren't there two other types of Alien called "Atavus" as well in EFC?). Howlyn falls in lust with Renee and wants her for his queen. Sandoval makes a deal with the Atavus and aligns himself with them. Renee meets Ra'jel, the Sire of the Synod and Yulyn, Howlyn's kind and gentle son...truly a Prince. Juda dies midseason as her portrayer, Guylaine st. Onge left to focus on treating her cancer. Then she died herself. Howlyn is killed by his first officer over a dispute and the first officer would have killed Yulyn if Renee hadn't stopped him. The Atavus Starship parts are used to fix the Mothership and the Atavus Starship explodes as the Mothership goes into interdimensional drive with Renee, Yulyn, Ra'jel and Liam on board, their wish is to explore the stars. Street ended up going from human to hybrid (under Sandoval's hybridization program) to human again and decides to stay at the Alamo Institute to help out there.