Try and install Plasma from a live CD provided by several Linux distributions.
The Fedora KDE Spin comes with Plasma. New minor Plasma versions are pushed as regular updates for Fedora installations but live media may contain a slightly older release (depending on Fedora’s release cycle).
- Plasma 4 is included in Fedora 21 KDE (maintained until 1 month after the release of Fedora 23).
- Plasma 5.3 is included Fedora 22 KDE (currently in beta).
- Kubuntu 15.04 comes with Plasma 5.2.