"There she is!" An alarm bell had finally sounded, the ultra-lights had flared out into space, and upon both screens there shone out images of the closely clustered wreckage of the _Arcturus_. But both men were more interested just then in the mathematics of the recovery than in the vessel itself. "Missed it eight minutes of time and eleven divisions on the scale," reported Stevens. "Not so good." "Not so bad either--I've seen worse computation." Thus lightly was dismissed a mathematical feat which, a few years earlier, before the days of I-P computers, would have been deemed worthy of publication in "The Philosophical Magazine." * * * * * Director Newton was called in, and it was decided that the many small fragments of the vessel were not worth saving; that its upper half was all that they should attempt to tow the enormous distance back to Tellus. The pace of the _Sirius_ was adjusted to that of the floating masses, and tractor beams were clamped upon the undamaged portion of the derelict, and upon the two slices from the nose of the craft. A couple of the larger fragments of wreckage were also taken, to furnish metal for the repairs which would be necessary. Acceleration was brought slowly up to normal, and the battle-scarred cruiser of the void, with her heavy burden of inert metal, resumed her interrupted voyage toward Europa; the satellite upon which the passengers and crew of the ill-fated _Arcturus_ had been so long immured. On she bored through the ether, detector screens full out and greenly scintillant Vorkulian wall-screens outlining her football shape in weird and ghastly light; unafraid now of any possible surviving space-craft of the hexans. But if the hexans detected her, they made no sign. Perhaps their fleet had been destroyed utterly; perhaps it had been impressed upon even their fierce minds that those sparkling green screens were not to be molested with impunity! The satellite was reached without event and down into the crater landing shaft the two enormous masses of metal dropped. Callisto's foremost citizens were on hand to welcome the Terrestrial rescuers, and revelry reigned supreme in that deeply buried Europan community. All humanity celebrated. The Callistonians rejoiced because they were now freed from the age-old oppression of the hexan hordes; because they could once more extend their civilization over the Jovian satellites and live again their normal lives upon the surface of those small worlds. The Terrestrials were almost equally enthusiastic in the reunion that marked the end of the long imprisonment of the refugees.