[link|http://www.sadgeezer.com/|Sadgeezer's] has a decent [link|http://www.sadgeezer.com/lexx/index.htm|LEXX section] with a very good [link|http://www.sadgeezer.com/lexx/ltreks.htm|Episode Guide]. They don't have season 4 guides added yet, though they do have screen grabs with a "coming soon" for the first episode "Little Blue Planet".
At the end of Season 3, Fire & Water are destroyed. The LEXX eats what he can(for non-LEXX viewers, the LEXX is a living space ship), but is still hungry. They start to leave and notice a planet, in the same orbit but on the exact opposite side of the sun, and proceed towards it in hopes of more food for LEXX. The episode fades out as the east coast of North America comes into view.
"Little Blue Planet", first Season 4 episode, opens in the past with Marconi's transatlantic test of morse code. A pullback to deep space reveals the test was a lot more success than he thought, as somebody's deep-space-probe(asteroid with lots of antenna) picks up the morse code. The probe's engines flare up when the signal is received. Back in current time, Prince(!) is the right-hand-man to the president and he's informing the president about the discovery of the LEXX, and how the ATF has killed off all the SETI people(blaming it on religous fanatics) to cover up the discovery. They also have the kid, who first discovered the LEXX, chained to the wall(same kid you might have seen next to Stan at the end of Episode 2), who first reported the discovery. They hold a conversation with Stan, who basically wants to be "satisfied", which goes not-so-well(per Prince's plans of course). The ATF releases a convicted psyco-killer(in the electric chair at the time the call comes in) who is sent up on the shuttle to kill off the crew of the LEXX. The shuttle is sent on a one-way mission, nuclear warhead included, to the LEXX. 790's concerned that "The Slut"(Xev) is after his dead man, and gives the killer enough info to kill Xev and get the key. He's about the kill Xev, but Kai intervenes just in the nic of time; however, the "key to the LEXX" sensed her impending death and returned to Stan. The nuke goes off, but the LEXX is impervious. 790 informs them it was a 24 megaton nuke, typical of a type 13 planet just prior to it's self destruction(due to war, shrinking into a black hole due to science experiement, etc). Because of the nuke(and failed discussion) Stan's conviced to blow up the planet and let the LEXX eat, but Xev decides to take Kai down to the planet first. The episode fades out with the asteroid on it's way - a bunch of things are now swarming around the asteriod, kinda-sort-like the "Matrid Arms" in series 2.
"Texx Lexx" opens with Xev & Kai's moth passing another shuttle. The shuttle carries Prince up to the LEXX. Prince, along with 790's help(he's conviced that Stan wants Kai too), captures Stan and takes him back to Earth where he's hung on the wall next to the kid from the last episode. Kai & Xev are attacked by stealth fighters who launch missles at them. They ask for 790's help, who doesn't want to help "because the slut could die but Kai won't", but Kai convinces him otherwise because "he'd need the moth to get back to 790." 790 recodes the signals and the missles distroy the stealth fighers. This exchange is observed by some "lone gunman"(ala the XFiles) The moth is attracted to the flame of a petrolium processing plant(somewhere in Texas) - the wings catch on fire, Xev jumps to safty and Kai goes down with the moth. Kai is picked up by the "lone gunman" people, who agree to help Kai provided he saves them from Earth because they know about the impending implosion of earth. They also reveal that the Lexx symbol(the circle figure below the word LEXX in the opening credits) is known in earth's history, and is associated with death. Xev learns how to hitchhike and is picked up by "Rooster" who falls in love with her, but won't go to bed with her until they are married(else he won't respect her). She's tells Rooster and his friends about her history(life as a love slave and all), and agrees to sleep with his buddies. Rooster's upset about this and chases everybody out. The next morning, Rooster and his buddies end up having a shoot-out and kill each other. The police eventually show up and arrest Xev for murder. The episode once again fades out with the asteroid & swarming mechanical things.
The dialog and character interaction where top-notch, and lots of little "fun" things happen during the course of the episodes(such as Xev's "Texas style" singing).
I'm sure there's some typo's or mispelled words - oh well :)