All I did was
sudo apt-get update
sudo apt-get install kubuntu-desktop
That installed the latest one for my distro and included Plasma.
Samsung Galaxy Precedent (rooted, AreaRom 3.4 , sd-ext w/ 3.65GB internal space)
Kindle Fire (1st Gen, rooted, AOKP JB 4.1, Nova Launcher)
Samsung Galaxy SIII 4G LTE (rooted, Carbon ROM)