From publisher blurb:
Siren's Song, a 4th level adventure for Aphelion's Gate: A Science Fiction Roleplaying Game, which introduces the Gamemaster and Players to The Galaxy of alien worlds and adventure. The Eridani Strain uses the D10 Pentra System, of which only a 10-sided die is needed to play this RPG adventure.
Galaxy Tours and Resorts has received a strange message from its resort on the moon Shravania Prime. A foreboding missive is hidden within the communication by the resort's staff. Stay away, it states, as the tourists have been infected by something unknown and have taken over the resort. Vacation time is over! So strap on your force screen, grab your laser pistol, concentrate on your Psi, prepare your starship for Hypershot, and blast off from Aphelion’s Gate!
The Aphelion's Gate INTRO rules can be used to play most of this adventure, though the CORE rules are needed to enjoy this entire adventure.