This time King of Prism is "Prism☆Tours"! Shin Ichijou and the other six members of SePTENTRION will travel across time and worlds in a time machine to the origins of Prism Shows. 
 
It will cross the boundaries of the series and intertwine with the worlds of the "Pretty Rhythm" series, "PriPara" series , "Kiratto Pri☆Chan", and "Waccha PriMagi!" to deliver a sparkling Prism☆Tours.
 
Fated boy meets boy, our worlds are now connected by the prism's sparkle!
 
(Source: Official Website, translated)

KING OF PRISM -Your Endless Call- Minna Kirameke! Prism☆Tours