Help Nexus

Syntax cast 'nexus' <target>

This spell is virtually identical to portal (see 'help portal'),
with the only difference being that while portal creates a one-way
gate, a nexus spell makes a two-sided gate.  It also lasts longer
than the lower-powered portal spell.  Both spells require an
additional power source, the secret of which has been lost...

See also teleport, gate, portal, refresh portal